Fact-checked by Grok 2 weeks ago

Email client

An email client, also known as a mail user agent (MUA), is software that runs on a user's —such as a computer, tablet, or —to enable the sending, receiving, reading, and organization of electronic mail by connecting to remote mail servers. These programs facilitate communication through standardized protocols, including SMTP for outbound message transmission from client to server, POP3 for downloading messages to the local (often deleting server copies), and IMAP for synchronized access across multiple devices while retaining originals on the server. IMAP has become predominant in modern usage due to its support for real-time updates and multi-device consistency, contrasting with POP3's simpler, device-centric retrieval model. Email clients originated in the alongside early networked computing but evolved significantly with graphical user interfaces in the , shifting from command-line tools to feature-rich applications like (introduced in 1997) and open-source alternatives such as (launched in 2003). Notable characteristics include support for threaded conversations, attachment handling, filtering, and integration with calendars or contacts, though proprietary clients like Outlook often bundle enterprise features such as . Despite their ubiquity—handling billions of daily messages—email clients face persistent security challenges, including vulnerabilities to attacks that exploit user interfaces for credential theft, malware-laden attachments, and rendering flaws in emails that enable exploits like script injection. Client-side remains limited without extensions, exposing and content to interception during protocol handshakes, which underscores the tension between usability and robust protection in an era of heightened cyber threats.

History

Origins and early systems (1965-1980s)

The first precursor to email clients emerged in 1965 with the development of the command for 's (CTSS), created by Tom Van Vleck and Noel Morris to enable users on the same multi-user computer to exchange messages asynchronously. This intra-system tool operated via command-line instructions, allowing message storage and retrieval within the shared environment of up to 30 simultaneous users, primarily serving and regional academic users for coordination without real-time interaction. Its design highlighted the practical advantages of deferred communication in setups, where synchronous access was limited by resource contention. Networked email capabilities advanced in 1971 when Ray Tomlinson, working on the ARPANET precursor to the internet, modified the SNDMSG program—originally a local messaging tool on the TENEX operating system—to enable transmission between separate computers. Tomlinson's implementation introduced the "@" symbol to denote user-host separation in addresses, facilitating the first inter-machine message exchange and establishing basic client functions for composing, sending, and reading via command-line interfaces. ARPANET's packet-switching architecture causally enabled this by prioritizing reliable, store-and-forward delivery over circuit-switched telephony models, demonstrating email's superiority for non-urgent, distributed collaboration among researchers. By the early 1980s, email systems evolved with the standardization of the (SMTP) in 821, published in August 1982 by Jonathan Postel, which defined rules for reliable message relay across TCP/IP networks. This underpinned command-line clients like those on UNIX systems, including derivatives of SNDMSG and early mail utilities such as mailx, which technical users employed for retrieving and dispatching messages via terminal commands. These tools remained text-based and operator-dependent, reflecting the era's focus on efficiency for expert operators rather than broad accessibility, with usage data showing email comprising up to 75% of traffic by 1973 to underscore its proven utility in asynchronous, fault-tolerant networking.

Commercialization and graphical interfaces (1990s)

The proliferation of personal computers in the , coupled with the after the NSFNET decommissioning in , spurred the development of proprietary email clients featuring graphical user interfaces (GUIs) to serve non-technical users beyond academic and environments. These clients emphasized ease of use, integrating with emerging PC operating systems like Windows and Macintosh, and shifted from command-line tools to intuitive applications that supported broader consumer adoption. This era marked a transition to commercial models, where software vendors monetized features like enhanced attachment handling and filtering, aligning with the rapid expansion of dial-up service providers. Eudora, first developed in 1988 by Steve Dorner at the University of Illinois for Macintosh systems, pioneered graphical interfaces with drag-and-drop functionality and visual mailboxes, achieving widespread use among early internet users in the after commercialized it in 1991 with paid "Pro" versions offering advanced filtering and scripting. In parallel, , released in 1991 by the , provided a menu-driven, text-based built on the curses library for systems, making navigation more accessible for command-line users without requiring full graphical environments, and it supported IMAP for server-side management. advanced enterprise integration with , launched on January 16, 1997, as part of Office 97, which bundled , , and contacts into a Windows-native , rapidly gaining through pre-installation on and compatibility with Exchange servers. Standardization efforts underpinned this commercialization: RFC 1081, published in November 1988, defined POP3 as a for client retrieval of emails from servers, enabling reliable to local PCs and reducing dependency on always-on connections. Complementing this, RFC 1341 in June 1992 established , allowing emails to include non-text attachments like images and binaries in a structured format, which clients like Eudora and later implemented to support , driving richer communication and user engagement. These s facilitated the email volume surge post-1995, as commercial ISPs like onboarded millions, transforming from niche tool to daily staple with usage growing exponentially amid PC penetration rates exceeding 50% in U.S. households by decade's end.

Integration with internet standards and mobile (2000s-2025)

In the early 2000s, email clients increasingly adopted (IMAP), originally specified in 1986, to enable server-side email management and synchronization across multiple devices, facilitated by expanding access. Clients such as , released in version 0.1 during summer 2003 as an open-source successor to Mozilla Mail, provided robust IMAP support alongside features like rendering and junk mail filtering, appealing to users seeking alternatives to . This integration reflected practical demands for reliable access in an era of growing ubiquity, allowing offline caching while maintaining server fidelity. The proliferation of mobile devices drove further adaptations, with introducing push email capabilities in devices like the 5810 in 2002, delivering real-time notifications over cellular networks using protocols such as IMAP with proprietary extensions. Apple's launch in 2007 included the Mail app, supporting IMAP and POP3 for seamless retrieval on touchscreen interfaces, marking a shift toward consumer-oriented mobile email that prioritized intuitive synchronization. By the mid-2010s, mobile access accounted for over 55% of business email usage, underscoring the transition from desktop-centric to always-connected models amid smartphone adoption. From 2023 onward, email clients incorporated for enhanced functionality, with integrating Copilot in to automate email drafting, summarization of threads, and prioritization, features users reported as improving response efficiency. Similarly, Google's for enabled AI-driven search and reply suggestions, addressing inbox overload through predictive sorting. Market analyses highlighted productivity gains, such as reduced time on routine tasks, though effectiveness varied by implementation and user context, driven by escalating email volumes rather than external mandates. Thunderbird continued evolving with add-ons for basic AI-like filtering, maintaining its open-source viability into 2025.

Types and classifications

Desktop and standalone clients

Desktop email clients are applications installed directly on a user's computer, enabling local storage and management of messages independent of continuous connectivity. These clients retrieve messages via protocols such as POP3 or IMAP, downloading them to the local filesystem for offline access and processing. This architecture provides users with full control over their data, minimizing reliance on remote servers and allowing operations like searching and composing without network access. Prominent examples include , , and . Outlook, integrated with , supports enterprise environments through protocol compatibility and holds approximately 37% market share in email management tools, particularly dominant in business settings due to its calendaring and task integration. Thunderbird, an open-source client developed by , features extensible functionality via add-ons for customization, such as enhanced filtering and local folder management for archiving large volumes of messages. eM Client offers support for multiple protocols including POP3, IMAP, SMTP, and , with local synchronization for calendars, tasks, and contacts. Key advantages stem from local processing, which reduces in operations like message search compared to cloud-based alternatives, as emails are indexed on-device for rapid querying of extensive archives. Customization through plugins and themes allows tailored workflows, such as automated rules and third-party integrations, enhancing productivity for power users. In enterprise contexts, desktop clients like facilitate compliance with requirements by enabling on-premises storage, avoiding associated with web services. Empirical benchmarks confirm faster response times for local searches, with offline capability ensuring uninterrupted access during connectivity disruptions.

Webmail and browser-based clients

Webmail clients enable email access through standard web browsers, rendering interfaces via , CSS, and delivered over HTTP or from remote servers, thereby avoiding the need for dedicated local installations. This server-centric architecture prioritizes universal accessibility across operating systems and devices but trades off local processing power and direct handling for browser-dependent rendering. Prominent examples include Google's , launched on April 1, 2004, which offered 1 GB of storage—over 500 times the norm at the time—and pioneered asynchronous JavaScript techniques for dynamic updates without page reloads, predating the formal term coined in 2005. Microsoft's followed, entering public beta on July 31, 2012, as a rebranded evolution of Hotmail with integrated and features. These services leverage server-side processing for features like search indexing and filtering, with scripts handling user interactions. Real-time capabilities emerged through AJAX-inspired methods, allowing push-like notifications via long-polling or WebSockets, though early implementations required persistent connections. Offline support remained rudimentary until the 2010s, when (PWA) standards introduced service workers for caching messages and enabling queued actions during disconnection, as implemented in services like by 2025. Webmail's appeal stems from seamless deployment without downloads, contributing to substantial adoption; for instance, captured 24.17% of global email client opens in September 2025, per analytics of over 1.2 billion sessions, underscoring zero-install convenience amid rising multi-device usage. Critics argue that webmail's centralized model concentrates data on provider servers, heightening risks of unauthorized access, prolonged retention exposing archives to breaches, and potential by operators or governments, in contrast to decentralized local clients where users retain offline custody. Such vulnerabilities have prompted privacy advocates to favor self-hosted alternatives, citing instances where server-side storage facilitates broader beyond user intent.

Mobile and cross-platform clients

Mobile email clients are software applications tailored for smartphones and tablets, emphasizing touch-based , controls such as swipe-to-delete or , and deep with operating system features like native notifications and background to enable alerts without constant user intervention. These clients prioritize portability by adapting to smaller screens with simplified layouts, hierarchical folder views, and quick-reply previews, while optimizing for resource constraints inherent to battery-powered devices. Prominent examples include on , which leverages the device's push notification system for seamless integration with and third-party IMAP/POP accounts; the app, pre-installed on most devices and supporting Google's proprietary push mechanism for instant delivery; and Email on Galaxy devices, customized for with enhanced Knox security for enterprise users. Outlook's mobile app employs protocol to facilitate push notifications, syncing emails, calendars, and contacts across and ecosystems. These native clients often tie into vendor-specific ecosystems, such as Apple's Fetch or settings, to balance immediacy with power efficiency. Cross-platform clients like extend functionality across , , and desktop via unified account management and shared features, such as smart inbox sorting and collaborative drafting, without relying on web wrappers. utilizes IMAP extensions for battery-efficient , where the client maintains an open connection to the server for notifications rather than periodic polling, reducing energy consumption by up to 50% compared to fetch intervals under 15 minutes. Similarly, in clients like enables server-initiated pushes, minimizing wake-ups and data usage on mobile networks. In the , adoption surged with frameworks enabling hybrid development, though mobile apps favor native performance over Electron-based wrappers typically used for desktop. By 2025, trends include AI-driven , such as automated summaries in via integration, which condenses threads for rapid scanning, and prioritization algorithms in to flag urgent messages based on sender patterns and . Empirical indicates mobile devices account for approximately 55% of global email opens, reflecting a shift toward on-the-go workflows where users handle during commutes or brief intervals, supported by these optimizations. This has causally elevated responsive communication, with conversion rates from mobile-opened emails reaching 4.29% in marketing contexts due to immediate engagement.

Core protocols and architecture

Retrieval and access protocols

Email clients primarily retrieve messages using two standard protocols: the Post Office Protocol version 3 (POP3), which downloads messages to the local device and typically removes them from the server, and the Internet Message Access Protocol (IMAP), which maintains messages on the server while synchronizing client views of folders and states. POP3, defined in RFC 1081 in November 1988 and later updated in RFC 1939 in May 1996, operates by connecting to the server (default port 110), authenticating, and retrieving all new messages in a single maildrop, after which it deletes them from the server unless configured otherwise, making it efficient for users with limited server storage or single-device setups where offline access is prioritized. This model minimizes ongoing server bandwidth but risks data loss if the local device fails, as copies are not retained server-side by default. In contrast, IMAP, first formalized as version 2 in 1064 in July 1988 and evolved through IMAP4 in 1730 in December 1994, supports server-side storage, folder management, and real-time of flags, reads, and deletions across multiple clients, using default port 143. IMAP4rev1, specified in 2060 in December 1996 and obsoleted by 3501 in 2003, introduced advanced search capabilities, such as querying messages by , sender, or keywords without full downloads, enhancing efficiency for large mailboxes and low-bandwidth scenarios. This server-centric approach empirically favors modern multi-device usage by preserving message integrity against local hardware failures and reducing redundant data transfers, as evidenced by widespread adoption in enterprise environments where IMAP minimizes errors compared to POP3's one-way retrieval. Secure variants use ports 995 for POP3S and 993 for IMAPS, wrapping the protocols in TLS without altering core retrieval logic.

Submission and transport protocols

The (SMTP) serves as the foundational standard for submitting and transporting outbound email messages from clients to mail transfer agents (MTAs). Defined in 821 and published in August 1982, SMTP enables clients to relay messages to a designated , which then forwards them across the network toward recipients' domains. This protocol operates primarily over port 25 for server-to-server transfers but distinguishes client submission via port 587, as specified in 6409 for message submission, ensuring authenticated handoff to prevent unauthorized relaying. Extended SMTP (ESMTP), outlined in RFC 1869, enhances the base by allowing servers to advertise supported capabilities during the initial session, such as larger message sizes or handling. mechanisms, introduced via the SMTP AUTH extension in RFC 4954, require clients to provide credentials—typically using methods like PLAIN or LOGIN—before submission, mitigating risks from unauthenticated access. Email clients initiate a session with commands like HELO/EHLO, AUTH, MAIL FROM, RCPT TO, and DATA to encapsulate and transmit the message envelope and content. In practice, email clients queue unsent messages in a local outbox when server connectivity fails or submission is deferred, periodically retrying until success or a threshold is reached, a behavior essential for offline resilience. While proprietary protocols like Microsoft's Messaging Application Programming Interface (MAPI) handle internal transport in environments such as Exchange Server for Outlook clients, SMTP remains dominant for cross-domain interoperability due to its standardization. The original SMTP design permitted open —allowing any client to forward mail through intermediate servers—which causally enabled widespread proliferation in the late and early , as spammers exploited unsecured MTAs to anonymize and amplify bulk sends. This vulnerability prompted the near-universal closure of open relays by 2002 and mandatory client , shifting submission to verified channels and reducing relay abuse from hundreds of thousands of exploitable servers to negligible levels. Modern clients thus incorporate pre-submission validation, such as domain checks and , to align with these evolved norms while preserving SMTP's relay efficiency.

Security and authentication protocols

Email clients rely on transport-layer security protocols to encrypt between clients and servers, primarily using TLS via mechanisms like STARTTLS for SMTP, IMAP, and POP3. STARTTLS, defined in 2487 for SMTP in January 1999, enables by upgrading plaintext connections to TLS after negotiation, though it requires both client and server support. For IMAP, similar extensions under 2595 facilitate STARTTLS on port 143 before switching to secure mode. Implicit TLS variants, such as on port 465 and IMAPS on port 993, establish encrypted connections from the outset without negotiation, reducing exposure to initial exchanges. Authentication protocols complement encryption by verifying user credentials without transmitting passwords in clear text. OAuth 2.0, standardized in 6749 in October 2012, supports token-based in modern clients, allowing delegated access to email services like without storing long-term credentials locally. This shifts from traditional methods like CRAM-MD5 or DIGEST-MD5, which, while secure against replay attacks, remain vulnerable if not paired with TLS. Client implementations vary: enforces strict TLS defaults, requiring version 1.2 or higher since version 78 in 2020 and disabling weaker ciphers by default to prioritize secure handshakes. Legacy clients, however, often permit fallback to unencrypted ports or outdated TLS versions, increasing risks in mixed environments. Adoption of these protocols has empirically boosted encrypted email traffic, with studies from 2015 showing STARTTLS support in over 80% of major SMTP servers, correlating with reduced passive opportunities, though active man-in-the-middle (MITM) incidents persist due to incomplete enforcement. Port 465 for and 993 for IMAPS, formalized in IANA assignments, have seen preferential use in submissions, aiding mitigation of initial leaks observed in port 25 or 587 scans. Despite these gains, STARTTLS remains susceptible to downgrade attacks, where adversaries strip the STARTTLS capability advertisement, forcing fallback; audits highlight this as a core flaw, prompting recommendations for implicit TLS or policy enforcement via MTA-STS. Such vulnerabilities underscore that protocols provide probabilistic protection, dependent on rigorous client-side validation and server compliance, rather than absolute guarantees against determined .

Primary functionalities

Message retrieval and synchronization

Email clients retrieve incoming messages primarily through periodic polling or server-initiated push mechanisms to balance efficiency and responsiveness. In polling, the client connects to the at configurable intervals, such as every 5 to 30 minutes, to query for new or updated messages, which conserves resources but introduces . retrieval, supported in IMAP via the command, allows the client to maintain an open connection where the notifies of arrivals or changes, enabling near-real-time updates without constant reconnection. Synchronization involves mapping server folders to local structures and applying delta updates to minimize data transfer. Clients track unique identifiers—such as UIDs in IMAP—to detect additions, deletions, or modifications, fetching only rather than entire folders, which reduces and processing overhead. Folder mapping ensures hierarchical consistency, with clients subscribing to specific folders for targeted sync, though mismatches can arise from server-side reorganizations. To prevent duplicates during retrieval, clients employ identifier-based checks: POP3 implementations often use UIDL lists to mark downloaded messages, but multi-client setups frequently result in redundancies if server deletion is enabled or intervals overlap. IMAP clients leverage stable UIDs across sessions for reliable deduplication, though user reports indicate POP3 configurations yield higher duplicate rates, with errors compounded by incomplete local tracking. Upon retrieval, clients organize messages into threads using headers like In-Reply-To, References, or normalized subject lines to group conversations, prioritizing message IDs for accuracy over subject matching alone, which can falter with edits. This client-side threading reconstructs sequences post-sync, aiding coherence without server dependency. Empirically, POP3 synchronization exhibits more frequent errors in multi-device environments, as one-way downloads disrupt shared access, leading to missing or duplicated items across clients; IMAP's server-centric model mitigates this, though initial syncs may lag due to folder enumeration. User accounts from forums report POP3-induced discrepancies in up to 20-30% of multi-client sessions, resolved by migrating to IMAP for bidirectional consistency.

Composition and editing

Email clients facilitate message composition through user interfaces that include fields for recipients, subject lines, and body content, adhering to the Internet Message Format specified in RFC 5322, which defines the syntax for headers and body structure to ensure interoperability across systems. The body supports plain text or formatting, with clients typically offering toggles between these modes to balance simplicity and visual enhancement. To incorporate attachments or mixed content types, clients employ the Multipurpose Internet Mail Extensions () standard, which structures messages as multipart entities—such as multipart/mixed for attachments or multipart/alternative for and versions—allowing non-ASCII text, images, and files while preserving standards compliance per RFC 2045. MIME types, derived from file extensions or user selection, dictate how recipients' clients interpret and render attachments, reducing errors in cross-platform handling. Common editing features include integrated spell-checking, which scans for orthographic errors in using built-in or system dictionaries, and support for message templates that pre-populate recurring content like signatures or standard responses to streamline repetitive tasks. composition enables bold, italics, lists, and inline links via editors, but empirical testing across campaigns shows plain text variants yield higher open and click-through rates due to fewer rendering inconsistencies and spam filter triggers in diverse clients like and . Non-compliant , such as unsupported CSS or excessive scripting, exacerbates compatibility issues, underscoring the reliability of for universal delivery.

Sending, queuing, and management

Email clients manage outgoing messages by initiating transmission immediately after composition when connected, but defer to a local if availability is absent or insufficient. This outbox queuing stores messages persistently on the device, enabling deferred submission via protocols like SMTP upon reconnection, thus isolating user actions from transient connectivity failures. In cases of intermittent , such as mobile data fluctuations, queuing ensures composed content is not lost by automatically retrying sends at configurable intervals without user re-entry, a causal safeguard against volatility observed in empirical network traces. Error recovery relies on Delivery Status Notifications (DSNs), formalized in RFC 1891 (1996) as an SMTP extension for reporting delivery outcomes, including permanent failures like invalid recipients that generate bounce messages returned to the sender's inbox. Clients parse these DSNs to alert users, facilitating actions such as address verification or message resending, distinct from server-side retries. Outgoing management includes user oversight of the , where unsent items can be edited, deleted, or prioritized before transmission, alongside post-send organization into dedicated folders with retention for auditing. This local contrasts with server-dependent systems, reducing dependency on remote error propagation.

Security and privacy considerations

Encryption mechanisms

Email clients primarily secure message transit through protocols, often invoked via the STARTTLS command, which upgrades connections for protocols like SMTP, IMAP, and POP3 to encrypted channels, preventing interception by intermediaries during client-server communication. This opportunistic or enforced TLS support is standard across major clients, including , , and , though it does not protect content once messages reach servers. For end-to-end protection of message content against server or provider access, clients implement standards such as , first developed in 1995 and relying on (PKI) for certificate-based signing and encryption, and OpenPGP, an open protocol defined in RFC 4880 for asymmetric key cryptography enabling encryption, signatures, and without centralized authorities. Both mechanisms require users to generate key pairs, exchange public keys securely, and verify identities, but key management complexities—such as manual distribution, revocation handling, and trust model validation—create substantial barriers, often resulting in misconfigurations or abandonment. Client-specific implementations vary in automation: Mozilla Thunderbird integrates native OpenPGP support since version 78 (released June 2020), allowing and but necessitating manual setup for recipients' keys and ongoing maintenance. Conversely, Proton Mail's clients automatically enforce for intra-service emails using an OpenPGP-compatible scheme where keys are derived from user passwords, simplifying the process for Proton-to-Proton exchanges while requiring password-sharing for external recipients to achieve comparable protection. These differences highlight trade-offs between standards-based and proprietary ease-of-use. Despite technical maturity, end-to-end encryption adoption in email remains limited, with usability hurdles in key handling cited as the dominant factor; studies indicate general user uptake below 20% as of 2025, even as market demand for encryption tools grows amid rising data breach concerns.

Vulnerability risks and mitigations

Email clients are susceptible to client-side vulnerabilities primarily arising from the rendering of malicious HTML, JavaScript, or attachments in emails, which can exploit flaws in the underlying browser engines or parsing libraries used for display. For instance, Mozilla Thunderbird, which relies on the Gecko rendering engine, has addressed multiple such issues, including arbitrary code execution vulnerabilities fixed in version 115.9 on March 19, 2024, via patches for CVE-2024-0743 and others that could crash the client or leak memory. Similarly, Microsoft Outlook faced CVE-2023-23397, disclosed in March 2023, where a specially crafted email triggered an NTLM hash leak without user interaction, enabling potential authentication bypass on Windows systems. These exploits highlight how legacy or unpatched clients amplify risks, as attackers craft emails to trigger buffer overflows or use-after-free errors during message rendering, distinct from server-side threats. Standalone desktop clients face heightened exposure compared to services due to user-dependent patching cycles and local execution environments, with CVE databases logging dozens of email client-specific entries annually, often tied to delayed updates. Unpatched installations, common in enterprise or personal setups without auto-update enforcement, prolong windows for exploitation; for example, 's 2025 advisories for version 144 addressed high-impact flaws like memory corruption on October 14, 2025, underscoring ongoing rendering engine risks inherited from . or extension ecosystems exacerbate this, as third-party add-ons in clients like can introduce unvetted code paths vulnerable to injection, though fewer than browser extensions due to scoped permissions. Empirical data from vulnerability trackers indicate desktop clients incur more client-side CVEs exploitable via payloads than , where server-side rendering and centralized controls limit local code execution. Mitigations center on isolating rendering processes and enforcing rapid updates, with open-source clients like benefiting from community-driven audits and frequent security releases, such as the July 2025 patches for multiple arbitrary execution flaws. Sandboxing the email client's rendering engine—confining HTML/JS execution to restricted environments—prevents , as implemented in modern clients via OS-level isolation techniques like those in MITRE's Application Isolation guidance. Disabling unnecessary features, such as HTML rendering or risky plugins, reduces , while automatic updates and plugin vetting protocols address delay-induced risks; Thunderbird's model, with transparent advisories, enables quicker remediation than proprietary clients reliant on vendor timelines. Users mitigate physical and malware vectors by combining client hardening with endpoint protections, though causal analysis shows unpatched desktops remain riskier for zero-interaction exploits versus webmail's managed updates.

Privacy trade-offs in client design

Desktop email clients employing local storage architectures store retrieved messages on the user's device, thereby reducing reliance on repeated queries and minimizing exposure to provider that tracks access patterns, search behaviors, and session data inherent in services accessed via browsers. In contrast, interfaces, such as those from major providers, facilitate continuous monitoring through client-side scripts and logs, amplifying for and without user intervention. Synchronization protocols like IMAP, while enabling multi-device access in clients, require ongoing connections to fetch —including message IDs, subjects, sender/recipient details, timestamps, and folder hierarchies—which are transmitted unencrypted unless TLS is enforced, exposing this information to the server and potential intermediaries. This metadata leakage persists even in local clients due to design, as servers must synchronize state to prevent inconsistencies, though users can mitigate it by limiting sync frequency or using offline modes. Centralized clients from large technology firms illustrate acute trade-offs; for instance, scanned users' email content for personalized purposes until June 23, 2017, when it ceased this practice amid concerns, yet retained scanning for spam detection and other internal uses. Such designs prioritize and revenue models over data minimization, contrasting with decentralized, user-controlled clients that empirically curtail exposure by confining operations to local hardware and optional, user-initiated uploads. This favors architectures where emerges from reduced causal dependencies on remote , challenging assumptions that cloud-centric convenience inherently outweighs verifiable risks of pervasive .

Advanced features and user experience

Search, filtering, and

Email clients implement search functionality through either local indexing or server-side queries. Local indexing involves creating a searchable database of downloaded messages on the user's device, enabling rapid retrieval even offline and preserving privacy by avoiding repeated server transmissions. In contrast, server queries transmit search terms to the provider for processing against the full remote corpus, which supports access to undownloaded data but depends on connectivity and may introduce . Desktop clients like historically favored local search via Windows indexing for speed, though approaches now blend both to balance performance and completeness. Filtering and rely on user-defined rules to process incoming messages based on criteria such as sender, subject keywords, or attachments, automatically applying actions like into folders, applying labels, or archiving. These rules execute client-side for local mailboxes or server-side via protocols in IMAP setups, enabling auto- that organizes inboxes without manual intervention. indicates such custom filters mitigate email overload by streamlining organization, with systems like agent-assisted rules demonstrated to reduce processing time in office workflows. From 2023 to 2025, AI-driven categorization has advanced these capabilities, with features like Gmail's tabbed inbox (Primary, Promotions, Social) using to prioritize and segregate messages, and 's Focused Inbox applying AI to surface high-priority items while deferring others. Benchmarks show these AI tools boosting productivity, such as reducing email time by approximately 25% and Gmail's related smart features cutting composition efforts by up to 30%. However, studies on AI highlight persistent false positives, where legitimate emails are misrouted—e.g., into or low-priority tabs—necessitating user overrides and underscoring limitations in model accuracy for nuanced content.

Integrations with productivity tools

Email clients commonly integrate with calendar systems via protocols such as , which enables bidirectional synchronization of events and appointments between the client and remote servers. This allows users to manage schedules directly within the email interface, pulling in data from services like or self-hosted servers without manual imports. Similarly, the format (RFC 5545) supports exchange of task lists and reminders, facilitating interoperability with productivity apps that export or import .ics files for seamless workflow continuity. For (), clients like provide plugins that embed CRM functionalities, such as Salesforce integration, permitting automatic logging of emails, attachments, and meetings into CRM records. This setup logs correspondence without leaving the email client, syncing contacts, tasks, and events to reduce duplicate data entry. Other CRMs, including , offer email and calendar sync for Gmail and Outlook, auto-creating contacts from inbound messages and aligning appointments with sales pipelines. These integrations yield measurable productivity benefits by minimizing context-switching between applications. reports that users experience less time on manual data entry and app navigation, enhancing sales efficiency. In enterprise settings, CRM-email linkages automate task syncing, with implementations cited to save hours weekly on administrative logging. Calendar-task further supports this by enabling unified views of deadlines and notifications, though efficacy depends on compliance and client support, as non-native CalDAV in requires third-party synchronizers.

Customization and extensibility

Email clients with open architectures, such as , support user customization through installable themes that modify the interface's visual elements, including colors, icons, and layouts, accessible via the client's add-ons manager. These themes, distributed as lightweight extensions, enable rapid aesthetic adjustments without altering core functionality, with static themes providing predefined styles and dynamic ones supporting conditional changes based on user preferences or system themes. Extensibility in such clients extends to plugins and extensions, which integrate scripts for advanced modifications like injecting custom content into email displays or automating behaviors. Thunderbird's extension , for instance, permits developers to add components, process message content, or execute background operations, fostering an where third-party contributions expand capabilities such as organization or contact integration. This contrasts with platforms, where extensibility is constrained by browser security models and provider-imposed limits, often restricting users to basic theme toggles or approved scripts without deep code access. Open-source email clients inherently promote auditability in their extensible components, as publicly available code allows independent verification of plugin behaviors and integration points, mitigating risks of undisclosed modifications in proprietary ecosystems. This transparency reduces dependency on vendor updates, enabling users to fork or patch extensions for specific needs, a flexibility absent in closed webmail environments that enforce uniform compliance to prevent platform fragmentation.

Advantages, disadvantages, and comparisons

Benefits over webmail alternatives

Email clients enable offline access to email content, permitting users to read, compose, and organize messages without requiring an active connection, as correspondence is downloaded and cached locally on the device. This capability stems from protocols such as IMAP or POP3, which synchronize data to the client for independent operation until reconnection for sending or updates. Performance advantages arise from localized processing, where search, filtering, and rendering occur on-device rather than relying on repeated queries through intermediaries, resulting in lower and reduced demands. For instance, IMAP's design efficiency supports rapid local indexing, outperforming webmail's dependence on JavaScript-heavy interfaces that introduce rendering delays. Management of multiple accounts benefits from integrated interfaces in email clients, consolidating inboxes, contacts, and calendars into one application without necessitating separate sessions or tabs for each provider. This unification enhances efficiency, particularly for users handling professional and personal correspondence simultaneously. gains include diminished reliance on web-embedded trackers, scripts, and advertisements, as clients bypass ecosystems that load extraneous elements during webmail sessions. Users can verify this by operating clients without scripting extensions, maintaining full functionality unlike webmail, which often degrades without for dynamic content loading. In enterprise settings, local storage facilitates compliance with policies through verifiable backups and reduced dependence on remote servers, aligning with the sector's preference for client software where adoption dominates due to needs and control requirements. Tools like exemplify this, serving hundreds of millions in business contexts for audit-ready local archives.

Drawbacks and common criticisms

Desktop email clients often require manual configuration of protocols such as , involving precise entry of server settings, ports, and authentication details, which can lead to errors and connectivity issues for non-technical users. This complexity contrasts with webmail's automated setup, contributing to user frustration and abandonment during initial use. Failure to promptly apply software updates exposes clients to known vulnerabilities, such as those in that enable if exploited via malicious emails. Delayed patching increases risks from email-delivered , as clients process attachments and links locally without inherent server-side protections. Desktop clients consume significant system resources, including CPU and , due to local indexing and caching of large mailboxes, leading to degradation on lower-end . faces specific criticism for feature bloat and practices that transmit user data, including email credentials in some versions, to Microsoft servers, raising concerns over unauthorized access and data harvesting. Empirical data from 2025 shows desktop clients hold only about 16% of email opens, compared to over 40% for , reflecting lower adoption among casual users who prioritize webmail's seamless accessibility across devices without or overhead. This disparity stems from desktop clients' setup and synchronization demands, which deter non-expert users despite advanced features.

Empirical adoption trends

Apple Mail commands the largest share of email client usage in 2025, accounting for 46.21% of global email opens as measured in September, primarily driven by device integration. Gmail follows with 24.17%, bolstered by its free access and cross-platform apps, while holds 3.52%, concentrated in enterprise environments via integrations. These figures, derived from over 1.2 billion analyzed opens, underscore the dominance of proprietary clients from major tech ecosystems, with , , and collectively exceeding 70% . Open-source alternatives like exhibit slower but steady niche adoption, appealing to users prioritizing customization and , though their overall share remains under 2% in aggregated open metrics. Gmail's user base surpasses 2.5 billion active accounts worldwide, reflecting broad consumer uptake facilitated by zero-cost entry and seamless mobile synchronization. In contrast, sustains around 400 million active users, predominantly in professional sectors where bundled productivity tools justify subscription costs. Mobile platforms have accelerated adoption shifts, with 41.6% of email opens occurring on clients in 2025, eroding reliance on desktop-only applications for non-enterprise users. Desktop opens have correspondingly declined to 16.2%, as consumers favor app-based access over traditional clients amid ubiquitous penetration. This trend correlates with economic incentives: free services like capture individual users through accessibility, whereas enterprises allocate budgets for feature-rich clients like to enable integrations and compliance. AI-enhanced features, including automated prioritization in and , correlate with elevated open rates on mobile, sustaining retention in high-volume scenarios without supplanting core economic drivers.

References

  1. [1]
    Definition of email client | PCMag
    What does email client actually mean? Find out inside PCMag's comprehensive tech and computer-related encyclopedia.
  2. [2]
    Definition of email program | PCMag
    Software in the user's computer, tablet or smartphone that accesses the mail servers in a local or remote network. Also known as an "email client," "mail ...
  3. [3]
    Email Protocols Explained: SMTP vs POP3 vs IMAP - Chamaileon
    Feb 20, 2023 · SMTP is for sending emails, POP3 is for retrieving emails, and IMAP is for accessing emails remotely. SMTP only deals with outgoing emails.
  4. [4]
    Email Protocols: What are the Different Ones? - Right Inbox
    The most common email protocols are IMAP, POP3, and SMTP. POP3 is for receiving, IMAP for remote access, and SMTP for sending emails.
  5. [5]
    IMAP vs POP3: Which email protocol is better? - Hostinger
    Sep 19, 2025 · Virtually all email clients support both IMAP and POP3. The choice is not about software compatibility but your personal or business needs.
  6. [6]
    POP vs. IMAP email protocols: What's the difference? - Mailgun
    IMAP synchronizes emails across multiple devices and keeps originals on the server, while POP downloads to a single device and deletes by default.What Are Email Protocols? · What Are The Main... · Pop Or Imap: When To Use...
  7. [7]
    The History of Email: Digging Into the Past, Present, and Future
    Nov 30, 2023 · The origins of email can be traced to the Massachusetts Institute of Technology (MIT) and the early days of computing. Back when computers were ...
  8. [8]
    A Brief History of Email Apps · Missive Blog
    In 1998, Microsoft bought Hotmail and Yahoo bought RocketMail. More recently Google bought Sparrow, Microsoft acquired Accompli and Dropbox grabbed Mailbox.
  9. [9]
    What is Microsoft Outlook? | Definition from TechTarget
    Mar 24, 2025 · Microsoft Outlook is an email, contacts and calendar program from Microsoft. The application also provides access to task management features.
  10. [10]
    7 Biggest Email Security Threats in 2025? - Keepnet Labs
    Jan 17, 2024 · 7 Biggest Threats to Email Security · 1. Domain Squatting (Cybersquatting) · 2. Phishing Attacks · 3. Malicious Attachments · 4. Ransomware · 5.
  11. [11]
    Common Email Security Issues and Mistakes to Avoid in 2025
    Apr 2, 2023 · Common email security issues include phishing, spoofing, misconfigurations, domain squatting, and client-side attacks, with email being the ...Missing: controversies | Show results with:controversies
  12. [12]
    The Case for Email Security | LuxSci
    Mar 21, 2025 · Find out exactly why email is inherently insecure and learn what can be done to improve your email security against the most common threats.Missing: controversies | Show results with:controversies
  13. [13]
    Encrypted Email and Security Nihilism | American Civil Liberties Union
    May 18, 2018 · This post examines the controversy, what people should do to secure their email, and how we might do better in the future.Missing: client | Show results with:client
  14. [14]
    Tom Van Vleck & Noel Morris Program "CTSS Mail", One of the First ...
    Tom Van Vleck & Noel Morris Program "CTSS Mail", One of the First Email Programs. . The two men created the program in the summer of 1965.
  15. [15]
    The History of Electronic Mail - Multics
    The Compatible Time-Sharing System (CTSS) was begun at the MIT Computation Center in 1961. By 1965, there were hundreds of registered users.
  16. [16]
    Electronic Mail and Text Messaging in CTSS, 1965 - 1973 - Multics
    [2] By 1965, there were hundreds of registered users from MIT and other New England colleges, and CTSS provided service to up to 30 simultaneous users every ...
  17. [17]
    Who Invented Email, Email History, How Email Was Invented
    In the early 1970's, Ray Tomlinson was working on a small team developing the TENEX operating system, with local email programs called SNDMSG and READMAIL. In ...Missing: client | Show results with:client
  18. [18]
    Email - from the beginning to the number one means of ... - MailStore
    Jul 5, 2023 · 1971: Ray Tomlinson sends the first email. · 1973: The first email standard, with functions such as “from”, “to” and “forward” is developed.The First Email – How It All... · Milestones in Early Email History
  19. [19]
    A Brief History of the Internet - Internet Society
    In March Ray Tomlinson at BBN wrote the basic email message send and read software, motivated by the need of the ARPANET developers for an easy coordination ...
  20. [20]
    RFC 821 - Simple Mail Transfer Protocol - IETF Datatracker
    Mar 2, 2013 · Simple Mail Transfer Protocol RFC 821 part of STD 10 ; RFC - Internet Standard (August 1982). Obsoleted by RFC 2821. Obsoletes RFC 772, RFC 780, ...
  21. [21]
    RFC 821 - Mailrelay
    RFC 821, or “Request for Comments 821”, is a technical document published in August 1982 that defines the SMTP protocol (Simple Mail Transfer Protocol).
  22. [22]
    When was the first SMTP email sent? The History of SMTP. - Prolateral
    Rating 4.2 (9) Jonathan Postel published the RFC821 in early August 1982 detailing the SMTP protocol. Later in the same month David Crocker published the RFC822 which detail ...
  23. [23]
    Getting America Online: The Spread of the Internet in the 1990s
    Mar 23, 2017 · The 1990s were a critical decade for the development and proliferation of the internet, with AOL leading the way in spreading and increasing the accessibility ...
  24. [24]
    The History of Email - Mailpro
    The 1990s witnessed an even more dramatic shift as email entered the personal sphere of everyday users. This period saw the rise of commercial internet service ...
  25. [25]
    Eudora History: Email for a Different Era - Tedium
    Sep 28, 2017 · The early graphical client Eudora was how people checked their email in the '90s. But in the end, only the power users stuck around. Here's what you missed.
  26. [26]
    Computer history Museum releases Eudora email client source code
    May 23, 2018 · One of the first popular email utilities to feature a graphical user interface was Eudora, created for Mac computers by Steve Dorner in 1988.
  27. [27]
    The Eudora™ Email Client Source Code - Computer History Museum
    May 22, 2018 · We are pleased to release the Eudora source code for its historical interest, and with the faint hope that it might be resuscitated.
  28. [28]
    ii.com · All About PINE: POP, IMAP, NNTP, & ESMPT Client for Unix ...
    Sep 27, 2007 · Pine version 1 was released to the public in 1991 and was the first IMAP client “that had more than a 2-digit user community”!
  29. [29]
    The Origin, Development and History of Outlook - Lookeen
    Jun 15, 2023 · Outlook was first introduced as part of the Microsoft Office suite in 1997, replacing Microsoft's earlier email program, Microsoft Mail.
  30. [30]
    Microsoft Announces the Immediate Availability of Office 97 - Source
    Microsoft Corp. today announced the immediate availability of Office 97, the new version of the world's ...
  31. [31]
    RFC 1081 - Post Office Protocol: Version 3 - IETF Datatracker
    The Post Office Protocol - Version 3 (POP3) is intended to permit a workstation to dynamically access a maildrop on a server host in a useful fashion.Missing: 1992 | Show results with:1992
  32. [32]
    RFC 1341 - MIME (Multipurpose Internet Mail Extensions)
    MIME (Multipurpose Internet Mail Extensions): Mechanisms for Specifying and Describing the Format of Internet Message Bodies · RFC - Proposed Standard June 1992
  33. [33]
    When Did Email Become Popular? A Review of History
    May 10, 2024 · Email was invented in the early 1970s as a way to communicate on ARPANET, the precursor to the internet. It gained widespread popularity in the 1990s.
  34. [34]
    https://nordvpn.com/blog/history-of-email/
  35. [35]
    Uncovering IMAP, The Email Protocol You Didn't Know You Needed
    Feb 23, 2023 · In the late 1990s and early 2000s, several popular email clients such as Apple Mail, Mozilla Thunderbird, and Novell GroupWise added IMAP ...
  36. [36]
    Thunderbird Time Machine: A Look Back At Thunderbird 0.1
    Jul 25, 2022 · Summer 2003: Linkin Park has the #1 album, Firefox doesn't technically exist yet, and a new email app called Thunderbird just launched...
  37. [37]
    Apple Mail - Wikipedia
    Mail, also known as Apple Mail, is an email client included by Apple with its operating systems macOS, iOS, iPadOS, watchOS, and visionOS. Mail grew out of ...
  38. [38]
    Email Usage by Businesses in the Last Decade - Intradyn
    By 2015, 55% of business emails were accessed via mobile devices, reflecting a growing trend toward mobile-first communication. ... The global market for email ...
  39. [39]
    AI Email Assistant for Outlook | Microsoft 365
    Features of AI in Outlook · Draft and respond to emails · Organize your inbox · Summarize information · Manage scheduling · Coordinate across apps · Help with tasks ...Missing: 2023-2025 | Show results with:2023-2025
  40. [40]
    The 9 best AI email assistants in 2025 | Zapier
    Aug 5, 2025 · Shortwave for AI-powered email search. Microsoft Copilot Pro for Outlook for improving communication. Gemini for Gmail for Google Workspace ...
  41. [41]
    Microsoft 365 Copilot vs. Google Gemini & Slack AI
    Jul 29, 2025 · Masterful Summarization: The ability of Copilot in Outlook to summarize long, convoluted email threads is a universally loved feature. Users ...
  42. [42]
    Thunderbird Email Client Review 2025: Still Worth Using?
    Rating 4.5 (3,300) Apr 28, 2025 · Thunderbird email client was initially released in 2003, but has it managed to keep up with the times? In this review, I'll examine whether ...Missing: origin | Show results with:origin
  43. [43]
    What Is an Email Client? 5 Different Types of Email Clients - CRM.org
    May 27, 2025 · Offline Access: Unlike webmail services that require an internet connection, email clients allow you to access your messages even when you're ...<|separator|>
  44. [44]
    Webmail Vs Desktop Email Client: Pros And Cons - Hostragons®
    Sep 30, 2025 · These clients download emails locally to your device for offline access and typically offer more advanced features and customization options.
  45. [45]
    Microsoft Outlook - Market Share, Competitor Insights in Email ...
    Microsoft Outlook has market share of 37.25% in email-management market. Microsoft Outlook competes with 130 competitor tools in email-management category. The ...Missing: desktop | Show results with:desktop
  46. [46]
    Add-ons for Thunderbird
    SmartTemplates offers an easy and powerful way to automatically create customized replies by auto-inserting various mail headers. Templates can be created ...
  47. [47]
    Features - Email - eM Client
    eM Client is the best equipped email client on the market, thanks to its support of virtually all conceivable email technologies (POP3, SMTP, IMAP, Exchange, ...
  48. [48]
    The 6 best email clients for Windows in 2025 - Zapier
    Jul 14, 2025 · It's the best way to manage multiple accounts, access messages offline, and make use of powerful tools that can help quickly triage your inbox.
  49. [49]
    Email Client Software Analysis 2025 and Forecasts 2033
    Rating 4.8 (1,980) Jul 15, 2025 · The global email client software market is experiencing robust growth, driven by increasing demand for enhanced productivity tools and seamless ...Missing: 2000s- 2020s
  50. [50]
    What is an Email Client? And Do I Really Need One?
    Email clients can access your messages in offline mode using POP3 or IMAP. With POP3, since the emails are downloaded to your device, you can access them ...
  51. [51]
    10 Years On, Gmail Has Transformed the Web as We Know It - WIRED
    Apr 1, 2014 · Gmail took Ajax mainstream. It gave webmail a slick snappiness more akin to a desktop application, and it left clunky old Hotmail in the dust.
  52. [52]
    How Gmail Happened: The Inside Story of Its Launch 10 Years Ago
    Apr 1, 2014 · Before long, the approach would get the moniker AJAX, which stood for Asynchronous JavaScript and XML; today, it's how all web apps are built.
  53. [53]
    Celebrating 50 years of email | Google Workspace Blog
    Oct 29, 2021 · And when Gmail launched on April 1, 2004 with lightning fast email search and a storage limit of 1 GB—500 times more than prevailing inboxes of ...
  54. [54]
    Microsoft launches the preview of Outlook.com - Source Asia
    Today, Microsoft launched the preview of Outlook.com, a new, modern mail service for individuals.
  55. [55]
    Offline and background operation - Progressive web apps | MDN
    Jun 23, 2025 · Offline operation allows a PWA to provide a good user experience even when the device does not have network connectivity.Websites and workers · Offline operation · Background sync · Background fetch
  56. [56]
    Fastmail's webmail app now works offline, and it's glorious! - Coywolf
    Aug 26, 2025 · The independent and privacy-focused email service Fastmail has updated its Progressive Web App to support offline access to emails, calendars,
  57. [57]
    Email Client Market Share and Popularity - Litmus
    Discover the top 10 most popular email clients, identify email client market trends, and learn how to use the data to improve your email program performance.Missing: 2020s | Show results with:2020s
  58. [58]
    4 reasons not to use webmail apps - Consumer Reports
    Mar 6, 2013 · With webmail, past messages you retain, as well your list of contacts, could remain on the server—potentially exposed to hackers—for long time ...
  59. [59]
    Decentralized Email for Maximum Privacy and Security - Runbox Blog
    Mar 7, 2025 · The more centralized a service is, the more vulnerable it becomes to breaches, surveillance, and data misuse. We're not part of a massive, data- ...<|control11|><|separator|>
  60. [60]
    Dangers of Trusting Big Tech - SmarterTools
    Feb 19, 2025 · Centralized power could lead to abuse. With all that data flowing through Microsoft's servers, Microsoft gains deep insight into users' ...
  61. [61]
    Best email client of 2025 - TechRadar
    Jun 11, 2025 · According to the latest email statistics data from a reputable marketing source, the top five clients include Apple Mail, Gmail, Outlook, Yahoo ...
  62. [62]
    Best Email Apps for Android: Top 5 to Tidy Your Inbox - Latenode
    Dec 2, 2023 · Efficient User Interface Design. An intuitive user interface (UI) can make or break an email app's message management and account accessibility.
  63. [63]
    The 10 Best Email Apps for Android: 2025's Top Picks - Clean Email
    Rating 4.5 (3,300) May 16, 2025 · 1. Gmail: Best Overall. Although Google Gmail comes pre-installed on nearly every Android smartphone, this popular email client still takes the ...
  64. [64]
    Best Email Apps for Android in 2025 - Appy Pie Automate
    Sep 8, 2025 · Discover the best email apps for Android in 2025. Explore top tools like Outlook, Zoho Mail, Mailchimp, Mailgun, and more—plus the ...
  65. [65]
    Spark Mail — Smart. Focused. Email.
    Fast, cross-platform email designed to filter out the noise - so you can focus on what's important. Free download Buy now 4.8 • 154K ratingsMissing: Electron | Show results with:Electron
  66. [66]
    IMAP IDLE: instant push email notifications | Blog - Limilabs
    IDLE is an IMAP protocol extension described in RFC 2177. It allows an IMAP client to indicate to the server that it is ready to accept real-time notifications.Missing: ActiveSync | Show results with:ActiveSync
  67. [67]
    Microsoft® Exchange ActiveSync | Qboxmail Documentation
    This guide will help you configure mail, contacts, and calendars offered by Qboxmail through different clients by using the Microsoft® Exchange ActiveSync ...
  68. [68]
    Best Email Clients 2025: AI Features & Cross-Platform Guide - Spike
    Rating 4.6 (1,434) Jun 18, 2025 · 1. Spike: Best overall AI powered email experience; 2. Gmail: Reliable choice with strong ecosystem integration; 3. Microsoft Outlook: ...
  69. [69]
    Designing Emails For Humans And AI In Gmail's New Era - Attentive
    Sep 10, 2025 · Gmail's new AI-powered email summarization uses Google's Gemini technology to automatically generate concise summaries. This feature helps users ...
  70. [70]
    Mobile Email Engagement — 32 Statistics Every Marketing Leader ...
    Sep 27, 2025 · What percentage of emails are opened on mobile devices in 2025? Mobile devices account for 55% of all email opens globally, with some sources ...
  71. [71]
    Email Open Rates in 2025: Benchmarks and Best Practices
    Jul 4, 2025 · Email viewed on mobile devices generates over $1 billion in revenue, with a conversion rate of 4.29% and an open rate of 41.9%. In contrast, ...
  72. [72]
    RFC 1939 - Post Office Protocol - Version 3 - IETF Datatracker
    Jan 21, 2020 · The Post Office Protocol - Version 3 (POP3) is intended to permit a workstation to dynamically access a maildrop on a server host in a useful fashion.
  73. [73]
    IMAP vs POP3 vs SMTP - The Ultimate Comparison - Courier
    This article will explain the difference between IMAP, POP3, and SMTP. Learn the benefits and drawbacks of each protocol. Consider when to use each one.
  74. [74]
    What Are Email Protocols - POP3, SMTP and IMAP - SiteGround
    Sep 3, 2025 · The encrypted port for POP3 is 995 and works over TLS/SSL. IMAP ports. By default IMAP works on two ports like POP3: 143 – this is the default ...
  75. [75]
    RFC 821 - Simple Mail Transfer Protocol - IETF Datatracker
    Simple Mail Transfer Protocol · RFC - Internet Standard August 1982. Report errata. Obsoleted by RFC 2821. Obsoletes RFC 772, RFC 780, RFC 788 · RFC 821.
  76. [76]
    RFC 6409: Message Submission for Mail
    Submission Identification Port 587 is reserved for email message submission as specified in this document. Messages received on this port are defined to be ...
  77. [77]
    RFC 1869 - SMTP Service Extensions - IETF Datatracker
    This memo defines a framework for extending the SMTP service by defining a means whereby a server SMTP can inform a client SMTP as to the service extensions it ...
  78. [78]
    RFC 4954 - SMTP Service Extension for Authentication
    This document defines a Simple Mail Transport Protocol (SMTP) extension whereby an SMTP client may indicate an authentication mechanism to the server.
  79. [79]
    MAPI over HTTP in Exchange Server | Microsoft Learn
    May 9, 2025 · MAPI over HTTP is a transport protocol that improves the reliability and stability of the Outlook and Exchange connections.
  80. [80]
    Email Security | The return of the open relays - Spamhaus
    Dec 2, 2013 · The number of active open relays—which grew in number through 2001—stabilized at between 200,000 and 250,000 in 2002, and then began to decline.
  81. [81]
    RFC 2487 - SMTP Service Extension for Secure SMTP over TLS
    RFC 2487 SMTP Service Extension January 1999 ; 2.1 Terminology ; 3. STARTTLS Extension ; 4. The STARTTLS Keyword ; 5. The STARTTLS Command ...Missing: date | Show results with:date
  82. [82]
    Which SMTP Port to Use? Understanding ports 25, 465, & 587
    Both ports 587 and 465 support TLS, port 465 is used for implicit TLS but port 587 which uses startTLS is preferred because message communications aren't ...
  83. [83]
    RFC 6749 - The OAuth 2.0 Authorization Framework
    The OAuth 2.0 authorization framework enables a third-party application to obtain limited access to an HTTP service, either on behalf of a resource owner.RFC 2617 - HTTP Authentication · Oauth · RFC 5849 · RFC 9700
  84. [84]
    Thunderbird 78 FAQ - Mozilla Support
    Dec 5, 2020 · How to enable outdated security protocols TLS 1.0 and 1.1 · Open Config Editor (about:config). ≡ > OptionsPreferences > Find in Options ...After upgrading to Thunderbird... · How to enable outdated...
  85. [85]
    Security.tls.version.* - MozillaZine Knowledge Base
    Jul 9, 2016 · TLS 1.0 is the minimum required / maximum supported encryption protocol. (This is the current default for the minimum required version.) 2. TLS ...
  86. [86]
    [PDF] Neither Snow Nor Rain Nor MITM...An Empirical Analysis of Email ...
    Oct 28, 2015 · We argue that low adoption stems in part from two of the three most popular SMTP software platforms failing to protect messages with TLS by ...
  87. [87]
    What SMTP port should be used? Port 25, 587, or 465? - Cloudflare
    Port 587, which uses STARTTLS, remains widely supported and is still commonly used for encrypted email submission.<|separator|>
  88. [88]
    SMTP downgrade attacks and MTA-STS - APNIC Blog
    Oct 4, 2024 · Guest Post: Auditing prominent mail providers to discover how they handle email encryption and show how MTA-STS can help improve email ...
  89. [89]
    https://datatracker.ietf.org/doc/draft-ietf-dane-smtp-with-dane/15/
  90. [90]
    SMTP security via opportunistic DANE TLS - IETF Datatracker
    1. STARTTLS downgrade attack The Simple Mail Transfer Protocol (SMTP) [RFC5321] is a single-hop protocol in a multi-hop store & forward email delivery process.<|control11|><|separator|>
  91. [91]
    Getting notifications about new messages in mailbox (IMAP IDLE ...
    It wouldn't work with POP3 mailboxes as POP3 protocol doesn't support this. However, in case of IMAP protocol, it's possible to take advantage of IDLE feature.
  92. [92]
    email push vs fetch | MacRumors Forums
    Oct 7, 2014 · Generally, push is touted as better on battery life for normal people that email little or moderately, and fetch is better for heavy email users.<|separator|>
  93. [93]
    IMAP IDLE: The best approach for 'push' email - Imageway
    Jul 19, 2018 · IMAP IDLE is a good approach for providing the immediate email notification and delivery service of “push email”.Missing: ActiveSync | Show results with:ActiveSync
  94. [94]
    What we talk about when we talk about push | Fastmail
    Dec 21, 2016 · To avoid the need to poll constantly, IMAP has a mechanism called IDLE. A client can open a folder on the server, and then “idle” on it. This ...
  95. [95]
    mailFolder: delta - Microsoft Graph v1.0
    Jul 23, 2025 · This allows you to maintain and synchronize a local store of a user's mail folders without having to fetch all the mail folders of that mailbox ...
  96. [96]
    How can we use message: delta to sync ALL folders and subfolders?
    Oct 2, 2024 · Use delta query to track changes of messages in a folder hierarchy by tracking each folder individually. Example shows how to synchronize ...Synchronize mail enabled pubic folders and distribution groups o365Force Delta Sync for Migration Batch - Microsoft Q&AMore results from learn.microsoft.comMissing: mapping | Show results with:mapping
  97. [97]
    How to make sure that the multiple pop3 clients download the same ...
    Nov 14, 2009 · You should either track message IDs or date/time - message IDs is more robust, that'd be the solution I'd look into first.
  98. [98]
    Outlook is downloading duplicate emails from a POP3 account
    If all outlook's are configured for pop, set each one to a different time - 5,6,7,8 min. This will prevent them from overlapping mail checks. Of course, the ...
  99. [99]
    How do I stop receiving duplicate emails? - Microsoft Q&A
    Jan 23, 2024 · Check if your email account is configured to use POP3 instead of IMAP. If so, switch to IMAP as it is designed to prevent duplicate emails.POP3 Duplicate emails - Microsoft Q&AExchange Online receiving duplicate emails through POP3 Since 11/1More results from learn.microsoft.com
  100. [100]
    Why am I receiving duplicate emails? - DreamHost Knowledge Base
    If you do not have a specific reason to use a POP connection, it's highly recommended you update it to an IMAP connection instead.
  101. [101]
    Email threading - RelativityOne - Relativity Documentation
    Aug 22, 2025 · If the Conversation ID field is present for an email and mapped on the profile, it is used to group the email together with other emails first.Email threading overview · Email threading fields · How email threading handles...
  102. [102]
    Email threading and how to change your threading mode
    Sep 5, 2025 · Messages with the same subject line will be threaded together, only if the email recipients are the same. Messages will only thread by ...
  103. [103]
    The Top 4 Differences Between IMAP and POP3 - Spiceworks
    Apr 11, 2023 · IMAP and POP3 are email protocols used to access and manage emails on remote servers. IMAP enables more advanced email management and synchronization across ...
  104. [104]
    ‎POP3 vs IMAP & sync'ing | Comcast Business Support Community
    Nov 5, 2016 · The interchange between the email client and the server is very different between POP and IMAP. Only IMAP will present the same set of messages ...Missing: errors reports
  105. [105]
    Just moved from POP3 to IMAP, but IMAP is very laggy and slow ...
    Jan 12, 2023 · I just moved from POP3 to IMAP, but IMAP is very laggish and slow. How can we fix this in Thunderbird? Is it even possible to fix?Why are people using POP3 like it's IMAP? : r/Thunderbird - RedditHelp me decide on IMAP vs. POP3 : r/Thunderbird - RedditMore results from www.reddit.comMissing: errors | Show results with:errors
  106. [106]
    IMAP vs. POP3 vs. SMTP Explained - Mailbird
    Aug 2, 2022 · What are the key IMAP vs. POP3 differences and which one should you choose for your email client? Find out the answers in this post.
  107. [107]
    RFC 5322 - Internet Message Format - IETF Datatracker
    RFC 5322 specifies the Internet Message Format (IMF), a syntax for text messages sent between computer users in electronic mail.
  108. [108]
    RFC 2045 - Multipurpose Internet Mail Extensions (MIME) Part One
    This set of documents, collectively called the Multipurpose Internet Mail Extensions, or MIME, redefines the format of messages.Missing: composition | Show results with:composition<|separator|>
  109. [109]
    Multipurpose Internet Mail Extension (MIME) Protocol - GeeksforGeeks
    Oct 15, 2025 · Characteristics of MIME​​ Attachments: Allows emails to include multimedia files like images, audio, video and documents. Multipart Messages: ...Missing: composition | Show results with:composition
  110. [110]
    Improve Your Email Game with built-in Spell Check and AI Tools
    Feb 13, 2025 · When you compose an email, eM Client will check your spelling in real time and underline any errors it finds. You can then right-click on each ...Missing: composition templates
  111. [111]
    24 Useful Business Email Templates for Every Situation | Pipedrive
    Find the right words for every situation (internal communications, outreach, customer service and marketing) with these 24 business email templates.
  112. [112]
    The Results Are In: A/B Testing HTML vs. Plain Text Emails - Litmus
    Oct 23, 2020 · Our customers engaged a little bit better with our plain text style email, indicated by a slightly higher open and click-through rate.
  113. [113]
    The difference between HTML and plain text emails - Paubox
    Apr 23, 2024 · HTML emails are more prone to be filtered by spam filters if not properly designed, whereas plain text emails generally have fewer issues with ...Missing: empirical | Show results with:empirical
  114. [114]
    HTML Vs. Text Emails: Insights From 1000+ Campaigns - IInfotanks
    Rating 4.6 (1,451) Apr 30, 2025 · The data about plain text vs HTML email performance revealed unexpected patterns. Plain text emails had higher open rates, while HTML emails ...Missing: empirical | Show results with:empirical
  115. [115]
    What Does 'Queued Email' Mean and How To Fix It | Superhuman
    Oct 25, 2024 · How to solve queued email issues · Check your internet connection · Check for offline mode · Schedule send emails · Check your account space · Update ...
  116. [116]
    Why does Outlook queue outgoing emails - Microsoft Q&A
    Jun 20, 2024 · This article provides a solution to an issue where email messages remain in the Outbox folder for at least one minute before it's sent. Outgoing ...
  117. [117]
    Email Queued? Here's Why and How to Fix It - Cleanfox Blog
    Oct 6, 2025 · To fix emails stuck in the queue, first ensure you have a strong internet connection and disable Gmail's offline mode. Check if you've hit daily ...
  118. [118]
    What Does Queued Mean in Emails? - NewMail AI
    Aug 11, 2025 · A “Queued” email means your message is stuck and hasn't been sent yet. · It usually happens due to weak internet, full storage, or app syncing ...Aug 11, 2025 · Why Are My Emails Getting... · How To Avoid Emails Getting...
  119. [119]
    Email non-delivery report (NDR) and SMTP errors in Exchange Online
    Jul 18, 2025 · This notice is also known as a "bounce message" or "bounce-back message." The most common type of DSN is a non-delivery report (NDR) that ...
  120. [120]
    Canceling the sending of a queued email in Gmail for Android
    Sep 21, 2015 · Open tbe main menu list from the button at the top left and go to Outbox. The stuck queued email will be there and easy to delete.Missing: client | Show results with:client<|separator|>
  121. [121]
    STARTTLS vs SSL vs TLS Explained in 5 Minutes - Mailtrap
    Jul 27, 2024 · STARTTLS is not a protocol but an email protocol command. It's used to tell an email server that an email client (such as Gmail, Outlook, etc.) ...
  122. [122]
    SSL, TLS, and STARTTLS - Fastmail help
    SSL and TLS encrypt connections. TLS is SSL's successor. STARTTLS upgrades insecure connections to secure SSL/TLS connections.Missing: transport | Show results with:transport
  123. [123]
    [PDF] Understanding S/MIME - ZT Browser
    Feb 17, 2025 · The first version of S/MIME was developed by many security vendors in 1995, but no standard was formed. In 1998, S/MIME V2 was released and ...
  124. [124]
    Usability of End-to-End Encryption in E-Mail Communication - PMC
    Jul 14, 2021 · This paper presents the results of a usability study focused on three end-to-end encryption technologies for securing e-mail traffic, namely PGP, S/MIME, and ...
  125. [125]
    Everything You Need to Know About S/MIME Email Encryption
    Oct 8, 2025 · Widely used across various platforms and email clients. Cons of PGP: Generally requires manual key management; Trust relies on a web-of-trust ...
  126. [126]
    OpenPGP in Thunderbird - HOWTO and FAQ - Mozilla Support
    Jun 20, 2022 · Yes. Thunderbird 78 has built-in support for two encryption standards, OpenPGP and S/MIME. OpenPGP has been enabled by default since version 78 ...
  127. [127]
    Proton Mail encryption explained
    Proton Mail encrypts message bodies and attachments. Emails between users are end-to-end encrypted. Emails to non-Proton users are end-to-end if password- ...
  128. [128]
    The Struggle is Real: Overcoming Email Encryption Difficulties - Virtru
    Feb 17, 2023 · In this blog, we'll go into detail about why email encryption is so important, why it's so difficult, and how we can overcome those difficulties.
  129. [129]
    Security Vulnerabilities fixed in Thunderbird 115.9 - Mozilla
    Mar 19, 2024 · Security Vulnerabilities fixed in Thunderbird 115.9 · #CVE-2024-0743: Crash in NSS TLS method · #CVE-2024-2605: Windows Error Reporter could be ...
  130. [130]
    Security Vulnerabilities fixed in Thunderbird 144 - Mozilla
    Oct 14, 2025 · Mozilla Foundation Security Advisory 2025-84. Security Vulnerabilities fixed in Thunderbird 144. Announced: October 14, 2025; Impact: high ...Missing: patches | Show results with:patches
  131. [131]
    Security Advisories for Thunderbird - Mozilla
    Critical Vulnerability can be used to run attacker code and install software, requiring no user interaction beyond normal browsing.
  132. [132]
    Application Isolation and Sandboxing, Mitigation M1048 - Enterprise
    Jun 11, 2019 · Application Isolation and Sandboxing refers to the technique of restricting the execution of code to a controlled and isolated environment.
  133. [133]
    Why Use a Mail Client vs Webmail - The Thunderbird Blog
    Sep 10, 2024 · Email clients offer enhanced security features, such as encryption and digital signatures, to protect your sensitive information. With local ...
  134. [134]
    What is an email client, and should you use one? - Proton
    Jun 2, 2023 · Desktop email clients have some advantages over webmail. Here's why you might use a standalone email app instead of, or together with, webmail ...
  135. [135]
    Email isn't private - General - Privacy Guides Community
    Sep 7, 2024 · Email metadata is always exposed to collection because that is how the protocol works. Certain information must be externally viewable in ...Missing: risks | Show results with:risks
  136. [136]
    Why Email Isn't the Best Choice for Privacy and Security
    Email metadata is protected from outside observers with opportunistic TLS , but it is still able to be seen by your email client software (or webmail) and any ...Missing: risks | Show results with:risks
  137. [137]
    Google Says It Will No Longer Read Users' Emails To Sell Targeted ...
    Jun 26, 2017 · Google will no longer scan emails in Gmail accounts in order sell targeted advertising, the company said Friday.
  138. [138]
    Google Will No Longer Scan Gmail for Ad Targeting
    Jun 23, 2017 · Google plans to abandon its longstanding practice of scanning user email in its Gmail service to serve targeted advertising.
  139. [139]
    Why does Outlook now search server rather than local?
    Mar 31, 2024 · Local searches are performed when Outlook cannot establish a connection to the server, when server-side searches are slow due to network issues, ...The search results are different - Microsoft Q&AOutlook Search discards search operators - Microsoft Q&AMore results from learn.microsoft.com
  140. [140]
    Outlook 365 search results differ from online - Microsoft Community
    Sep 16, 2019 · Based on my knowledge, Outlook desktop search is based on Windows search, and online use server engine.
  141. [141]
    Manage email messages by using rules in Outlook - Microsoft Support
    At the top of the page, select Settings . · Select Mail > Rules. · Select a rule, and then use the Up arrow or Down arrow to change the order in which the rule is ...Auto forward messages · Import or export rules · Edit or fix a broken rule in...
  142. [142]
    Create rules to filter your emails - Gmail Help
    On your computer, you can manage your incoming mail using Gmail's filters to send email to a label, or archive, delete, star, or automatically forward your mail ...
  143. [143]
    What Is Auto-Sorting In Email: Setup And Benefits - Clean Email
    Rating 4.5 (3,300) Oct 24, 2024 · Auto-sorting occurs when you automatically organize and categorize incoming emails based on predefined rules or filters.
  144. [144]
    [PDF] Agent-Assisted Task Management that Reduces Email Overload
    Feb 10, 2010 · RADAR is a multiagent system with a mixed-initiative user interface designed to help office workers cope with email overload.
  145. [145]
    Gmail Statistics for 2025: Insights on Users and Trends - Clean Email
    Rating 4.5 (3,300) Mar 3, 2025 · Features like Priority Inbox and AI-powered email categorization significantly reduce the time users spend managing routine tasks, enabling ...Missing: benchmarks | Show results with:benchmarks
  146. [146]
    Outlook vs Gmail: Best Email Platform Choice for 2025 - CloudFuze
    Aug 14, 2025 · Outlook uses categories, a focused inbox, and offers AI features through Copilot. Gmail lets you apply labels, filters, and compose smart ...Missing: productivity benchmarks 2023-2025
  147. [147]
    AI tools for Outlook vs Gmail in 2025 - Virtualworkforce.ai
    Oct 4, 2025 · Compare AI in Outlook and Gmail to find the best AI email assistant for your inbox in 2025, with tips on email workflow and management.Missing: 2023-2025 | Show results with:2023-2025
  148. [148]
    [PDF] Enhancing Cyber Security: Comparing the Accuracy of the Bert ...
    Mar 30, 2025 · A major challenge in spam filtering is reducing false positives, which can lead to legitimate emails being incorrectly classified as spam ...
  149. [149]
    A stacking approach Machine learning for spam email detection - PMC
    Sep 3, 2025 · By aggregating predictions from diverse models, these approaches reduce both false positive and false negative rates while enhancing the overall ...Missing: custom | Show results with:custom
  150. [150]
    CalDAV API Developer's Guide | Google Calendar
    CalDAV is an extension of WebDAV that provides a standard for clients to access calendar information on a remote server. Google provides a CalDAV interface ...
  151. [151]
    How do I sync Synology Calendar with CalDAV clients?
    Apr 10, 2024 · This article shows you how to sync Synology Calendar with Mozilla Thunderbird, Microsoft Outlook, and CalDAV clients on Android, iOS, and macOS.
  152. [152]
    Synchronizing local clients with webmail calendars and contacts
    This article describes how to connect your local clients to webmail calendars and contacts using CalDAV and CardDAV.
  153. [153]
    Salesforce - Microsoft AppSource
    Rating 4.3 (6,506) The Salesforce integration with Outlook lets you experience Salesforce right in Outlook. The integration is 100% cloud-based with no software to push, install, ...
  154. [154]
    Integrate Salesforce with Outlook for Sales Productivity - Trailhead
    When you integrate Outlook and Salesforce, you help your reps spend less time entering data and switching between the two applications.
  155. [155]
    CRM Email & Calendar Sync For Gmail, Outlook, and more
    Easily sync your email and calendar with Nutshell to make your CRM work where you do. Learn more about our CRM & start a free 14-day trial!Conveniently Send And... · How To Sync Your Email &... · Crm Features That Boost Your...<|separator|>
  156. [156]
    Integrate Salesforce with Outlook for Easy CRM Automations
    Nov 6, 2024 · Improved Productivity: Sales reps save hours by automating tasks like syncing emails and events. Enhanced Customer Engagement: With Salesforce ...
  157. [157]
    Caldavsynchronizer – Sync Outlook Everywhere
    The Outlook CalDav Synchronizer offers a two-way synchronization of calendars, tasks and contacts between Outlook and several CardDAV providers. Open Source.
  158. [158]
    Install themes to change the look of Thunderbird - Mozilla Support
    Jul 16, 2024 · A theme is a type of Thunderbird add-on which changes the visual appearance of Thunderbird. This article describes how to find, install and manage themes in ...
  159. [159]
    A Guide to Themes - About Thunderbird
    Oct 1, 2025 · A theme is a Thunderbird add-on that allows to change the appearance of Thunderbird. This document covers the following topics: Static Themes.
  160. [160]
    A Guide to Extensions - About Thunderbird
    Oct 1, 2025 · An extension is a Thunderbird add-on, that provides additional functionality by adding new user interface elements, alter content, or perform background tasks.
  161. [161]
    Webmail vs. Email Clients: Which One is Right for You? - CanSpace
    May 22, 2025 · Security differs between the two options, with webmail relying on provider-based encryption and authentication, while email clients offer ...Missing: desktop | Show results with:desktop
  162. [162]
    Open-Source vs Proprietary Software: The Clear Winner in 2025 | O8
    Open-source software allows for personal and commercial use, modification, redistribution, and comes with varying licenses, making it cost-effective and ...The Pros And Cons Of Each · Proprietary Software · Open-Source Vs. Proprietary...
  163. [163]
    The benefits of using a desktop email client – Microsoft 365
    Jul 14, 2023 · Desktop email clients offer offline access, customization, easier workflow, more storage, advanced encryption, and more filtering options.
  164. [164]
    Webmail vs. Email Client - Doteasy
    Apr 30, 2024 · Webmail is accessed via a browser, while email clients are installed software. Webmail is portable, but email clients allow offline access and ...
  165. [165]
    Why do some people prefer to use an email client instead of a web ...
    Nov 15, 2022 · 1) The desktop email client is much faster than the webmail interface due to the fact that the IMAP protocol was designed to be very efficient ...Why and when should you prefer an email client to a web mail?What is the difference between an email client and a web-based ...More results from www.quora.com
  166. [166]
    Best Email Clients for Multiple Accounts in 2025 - Mailbird
    Oct 2, 2025 · With nearly two email accounts to manage per person, tools like Mailbird offer unified inboxes, calendar integration, and app connectivity, ...
  167. [167]
    What are the benefits to using email clients over webmail? - Reddit
    Jun 27, 2021 · Comments Section · possibility of end to end encryption · more control over how email is displayed · more control over elements loaded · less data ...Secure Emailing: Webmail vs. Desktop/Mobile Clients : r/privacyWebmail vs Open Source Email Client (like Thunderbird) - RedditMore results from www.reddit.com
  168. [168]
    Email Clients - Awesome Privacy
    A benefit of using an IMAP client, is that you will always have an offline backup of all email messages (which can then be encrypted and archived), and many ...
  169. [169]
    Outlook Statistics 2025: Usage, Trends & Insights
    Email Client Market Share: A Solid Position​​ Its email client market share is approximately 10%. This means that one out of every ten emails opened in the world ...
  170. [170]
    What Is Internet Message Access Protocol (IMAP)? - JumpCloud
    Sep 17, 2025 · Configuration Complexity demands accurate setup of both incoming IMAP and outgoing SMTP server settings. Users must configure multiple protocol ...
  171. [171]
    7 Reasons Why You Should Stop Using Desktop Email Clients
    1. Portability · 2. Security · 3. Multiple Computers = Multiple Setups · 4. Different Operating Systems · 5. Spam · 6. Longevity · 7. Cost · Learn More About Email ...2. Security · 4. Different Operating... · 5. SpamMissing: drawbacks | Show results with:drawbacks
  172. [172]
    Multiple Vulnerabilities in Mozilla Thunderbird Could Allow for ...
    Jul 9, 2025 · Multiple vulnerabilities have been discovered in Mozilla Thunderbird, the most severe of which could allow for arbitrary code execution.
  173. [173]
    Master Email Virus Protection: Effective Strategies and Best Practices
    May 1, 2024 · Promptly installing updates ensures these vulnerabilities are patched, reducing the risk of email viruses or malware exploitation.
  174. [174]
    https://mailsite.com/blog/microsofts-new-outlook-major-privacy-concerns-fewer-features
  175. [175]
    Microsoft's New Outlook: Major Privacy Concerns, Fewer Features
    Apr 27, 2025 · The new Outlook stores data on Microsoft's cloud, raising privacy concerns. It also lacks features like Exchange ActiveSync support and has ...Missing: bloat telemetry
  176. [176]
    Microsoft Outlook Update Raises Privacy Concerns | Blog - StartMail
    Nov 14, 2023 · Learn about the recent Microsoft Outlook update that may compromise your email privacy by transferring messages and credentials to Microsoft's ...Missing: bloat telemetry
  177. [177]
    13 Latest Email Client Statistics You Should Know - Mailmodo
    Jan 8, 2025 · Apple dominates the email client market with a substantial 58.67% share. · Gmail follows closely behind with a 28.72% market share in the email ...Missing: enterprise | Show results with:enterprise<|separator|>
  178. [178]
    Why you should stop using Desktop Email Clients
    Jun 21, 2019 · Many of the best desktop email clients cannot effectively handle spam. Sure, you can mark a particular message as spam in your client, but ...Portability · Multiple Devices, Multiple... · Spam
  179. [179]
    Litmus: Email Client Market Share in March 2025 - LinkedIn
    Apr 26, 2025 · Litmus analysed over 1.2 billion email opens in March 2025, revealing that four major players continue to dominate the email client landscape.Missing: enterprise | Show results with:enterprise
  180. [180]
    Thunderbird 139 Boosts Email Actions and Stability - WebProNews
    Jun 3, 2025 · The email client landscape has long been dominated by a few key players, but Mozilla's Thunderbird continues to carve out a significant niche, ...
  181. [181]
    Gmail Statistics (2025) – Market Share & Users Data - DemandSage
    Aug 20, 2025 · Over 2.5 billion people use Gmail in 2025, making it the second most popular email client ... Gmail holds a 25.89% share of the worldwide email ...
  182. [182]
    Outlook Statistics For 2025: Key Trends Shaping the Future
    Rating 4.5 (3,300) Mar 12, 2025 · It currently holds about 4.38% market share for email platforms. This places it among the top email platforms globally, and this is largely ...
  183. [183]
    Mobile Email Statistics 2025: Key Data & Trends You Need - SalesSo
    May 30, 2025 · Mobile clients account for 41.6% of email opens, followed by webmail opens at 40.6% and desktop opens at 16.2%. This shift represents one of the ...Missing: 2000s- 2020s
  184. [184]
    Gmail Statistics 2025: User Growth, Market Share & Emerging Trends
    Aug 6, 2025 · Gmail holds between 53% and 76% of the U.S. email client market share, depending on tracking methodology. Outlook's share remains under 10% ...