SnappyMail is a fast, privacy-respecting webmail client that connects to any existing IMAP and SMTP server, booting in under a second with a JavaScript payload of just 138 KB under Brotli compression (down from RainLoop's 8 MB fork origin). No database is required: all configuration and user data persists as flat files in a single volume, making Docker deployment trivially simple with the roughly 30 MB image consuming approximately 50 MB of RAM. Built-in PGP encryption supports three backends: OpenPGP.js v5 with ECDSA and EDDSA key generation, GnuPG integration, and Mailvelope browser extension compatibility, eliminating the need for separate encryption plugins. The integrated Sieve script editor enables users to create mail filtering rules, vacation auto-responders, and forwarding conditions directly within the web interface when connected to ManageSieve-capable servers on port 4190. Multi-domain administration allows a single instance to serve users across multiple IMAP servers with per-domain authentication routing. The admin panel manages extensions, security settings, branding customization, and domain configuration. GDPR-friendly by design, it removes all social media integrations, Gravatar lookups, and external tracking present in RainLoop. Dark mode strips background and font colors from email messages. The modified Squire HTML editor replaces CKEditor for composing rich-text messages. Scores 99% on Lighthouse performance. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.

Two decades of continuous development made Roundcube the standard-bearer of open-source webmail - a PHP IMAP client that gives any mail server a polished, application-like interface in the browser. It connects to whatever IMAP/SMTP stack you run - Dovecot, Postfix, a hosted mailbox - and delivers the full desktop-client experience: drag-and-drop message management, threaded conversation views, full MIME and HTML mail handling, find-as-you-type address book with groups and LDAP connectors, multiple sender identities, full-text search, and spell checking in dozens of languages. The default Elastic skin is genuinely responsive, working as well on a phone as a desktop, and the entire UI is skinnable. The plugin API is where deployments get shaped: managesieve exposes server-side filter management in the UI, enigma brings PGP encryption and signing via GnuPG, markasjunk trains spam filters, zipdownload batches attachments, password lets users change credentials, and attachment_reminder catches the classic forgotten-attachment email - among hundreds of community plugins. Built-in caching keeps large mailboxes fast, IMAP ACLs and shared folders support team setups, and XSS protection is engineered into the rendering pipeline. It scales from a single personal mailbox to unlimited users, backed by MySQL, MariaDB, PostgreSQL, or SQLite. GPL-licensed with regular security releases.

Kurrier unifies email, calendars, contacts, and file storage in a single web interface that connects to any email provider you already use. The Next.js frontend with Nitro API worker deploys via Docker Compose on PostgreSQL and Redis, delivering a cohesive workspace where IMAP/SMTP mailboxes from Gmail, Outlook, or corporate servers sit alongside transactional providers like AWS SES, SendGrid, Mailgun, and Postmark. Automatic inbox building handles threads, attachments, sent items, and deletion sync through persistent background polling. The CalDAV backend enables full two-way calendar synchronization with iOS, macOS, Android via DAVx5, and Thunderbird, supporting event invitations, RSVP processing through the inbox, timezone-aware scheduling, and contact-aware attendee linking. CardDAV contacts sync bidirectionally across all devices with unified name, avatar, and email resolution. Kurrier Drive provides integrated file storage through WebDAV locally or S3-compatible backends for cloud storage. Multiple identities and domains let you manage several email accounts from different providers in one interface, with fast local search indexing subjects, senders, and content without dependency on external APIs. The API-first architecture exposes clean endpoints for automation and custom integrations. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.

SOGo adds shared calendars, address books, and a modern webmail interface to your existing Dovecot, Postfix, or Cyrus mail setup, turning familiar infrastructure into a full Exchange competitor. Rather than replacing your IMAP and SMTP servers, SOGo layers collaboration on top of them, becoming the missing link between raw mail delivery and what users actually expect from a workplace communication platform. The ActiveSync implementation synchronizes email, contacts, calendars, and tasks natively with iPhones, Android devices, and Windows without requiring users to manually configure CalDAV endpoints. CalDAV and CardDAV compliance ensures Apple Calendar, Thunderbird (via the official SOGo Connector extension), GNOME Evolution, and Android via DAVx5 all connect without plugins or workarounds. The web interface uses AngularJS Material design with responsive layouts, offering folder management, drag-and-drop calendar scheduling, contact groups, resource booking, and delegation. Shared calendars support free-busy lookups, iMIP event invitations, and per-user ACL permissions for fine-grained access across organizational units. Built on Objective-C with the GNUstep foundation, SOGo delivers exceptional performance: hundreds of concurrent ActiveSync connections from mobile devices alongside webmail and calendar traffic with sub-second response times. With 2,095+ stars and 116 releases, the project has proven its stability in production environments supporting thousands of users. The Docker deployment runs alongside PostgreSQL and memcached.

Transforming your Stalwart Mail Server into an all-in-one private communication hub, Bulwark Webmail delivers fast web-based email, collaborative calendars, shared contacts, and cloud files in a single unified interface. Users can manage multiple email accounts from an integrated inbox with conversational message threading, nested organizational tags, scheduled delivery, and instant full-text search across thousands of archived messages. The rich text composer provides markdown shortcuts, inline image embedding, reusable canned response templates, and automated draft synchronization. Team members can coordinate schedules across day, week, month, and agenda calendar views with drag-to-reschedule adjustments, interactive iMIP meeting invitations, and external CalDAV calendar subscriptions. The integrated address book organizes individual contacts into custom groups with full vCard import and export support, while the files module lets users browse server storage, preview incoming attachments, and upload documents directly through the browser. Built-in security safeguards enforce multi-factor authentication, cryptographic S/MIME signatures, client-side encryption at rest, and automated HTML luminance remapping to keep dark emails legible. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL v3 licensed.

DispatchMail is an SuperHuman alternative and delivers a self-hosted AI email assistant that processes your Gmail inbox through configurable OpenAI prompts without sending data to third-party cloud services beyond the LLM API itself. The Flask backend connects to Gmail via IMAP, retrieves new messages according to your schedule, and routes them through customizable whitelist rules based on sender address, subject keywords, or natural language descriptions before AI processing begins. Two distinct prompt configurations control behavior — the Reading Prompt instructs how the AI should analyze and classify incoming messages, while the Draft Prompt defines how responses should be composed, letting you maintain consistent tone and policy across all automated replies. Whitelist filtering ensures the AI only processes messages you explicitly authorize, preventing unnecessary API costs and keeping sensitive emails out of the LLM pipeline entirely. The React web interface provides inbox management with message previews, AI-generated summaries, draft editing with human-in-the-loop approval before sending, and configuration panels for prompts and rules. Automatic labeling and archival organize processed messages into categories without manual intervention. The sender research feature uses LLM-powered deep analysis to build background profiles of email contacts. All email content, credentials, and processing results persist in a local SQLite database with zero cloud storage dependencies. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache-2.0 licensed.

Your Gmail, Google Workspace, or Outlook inbox, worked by an AI assistant: Inbox Zero sits on top of the account you already have. Its core idea is rules written in plain English - tell the assistant "label invoices and file the PDF to Drive" or "archive cold outreach unless they mention my company" - and it executes against every incoming message. Emails that need a response arrive with a pre-drafted reply written in your tone, learned from your email history and calendar context. Reply Zero tracks what you owe responses to and what you're waiting on; the Bulk Unsubscriber surfaces newsletters you never read (with read-rate analytics) for one-click unsubscribe-and-archive; the Cold Email Blocker auto-archives unsolicited pitches based on your own definition of "cold." Smart Filing routes attachments - receipts, contracts, PDFs - into the right Google Drive or OneDrive folder, and Slack/Telegram integration lets you read, draft, and triage without opening a mail client. Email analytics show top senders and volume trends. It is not a new email client: everything happens in your real mailbox using native filters. Self-hosting means your mail content and the LLM calls that process it run on infrastructure you control.

Zero unifies Gmail, Outlook, and IMAP accounts into a single AI-enhanced inbox with keyboard-driven navigation that matches premium email clients in speed. Backed by 10,000+ stars and positioned as the alternative to Superhuman, it keeps your email data in your own PostgreSQL database while LLM agents handle categorization, priority sorting, draft composition, and natural language mailbox queries. You choose whether models run locally or through cloud providers you control. The Next.js and React interface delivers customizable keyboard shortcuts for every action: reading, archiving, labeling, composing. A WorkflowEngine defines automated multi-step rules including label application, bulk archiving, and conditional routing based on sender, subject, or content analysis. Built on Drizzle ORM with Better Auth handling Google OAuth, styled with TailwindCSS and Shadcn UI components, the interface is polished without being bloated. MCP integration exposes email management tools to external AI assistants for programmatic inbox control through standardized protocols. The Nizzy CLI handles environment configuration, database synchronization, and development server orchestration. Deploys via Docker Compose with a single database initialization command. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Macro merges email, team chat, collaborative documents, task management, CRM, and video calls into one keyboard-driven application where AI agents operate across the entire workspace with shared team memory, replacing the Slack plus Notion plus Linear plus Superhuman plus HubSpot stack with a single deployment. The email module provides a multi-account unified inbox with keyboard shortcuts, shared team inboxes, and Gmail integration. Team messaging offers channels and direct messages designed for technical discussions with threaded conversations. The task system draws from Linear with board and list views tightly integrated with channels, email threads, and AI agents. Real-time collaborative documents use CRDT synchronization via Loro for conflict-free editing with Markdown-native formatting and @mention linking. A 2D canvas board embeds @links to tasks, files, and emails for visual project planning. AI agents access unified team-level memory spanning all workspace modules, taking autonomous actions across email, chat, tasks, and documents through MCP-compatible tool interfaces. Video calls include recording, transcription, and automatic logging to team memory. The CRM module tracks customers and contacts with custom properties, email synchronization, and data enrichment. Eighty-plus Rust microservices on the Axum framework handle backend operations while a SolidJS static SPA delivers the frontend with instant search and real-time collaboration. Docker Compose deployment provisions the complete service stack with PostgreSQL, Redis, OpenSearch, and FusionAuth authentication. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.

Calendars, to-do lists, journal entries, and contacts, synced over the open CalDAV and CardDAV standards nearly every client already speaks: Radicale is a small pure-Python server that works with Thunderbird, DAVx5 on Android, Apple Calendar and Contacts, GNOME, and many more. Its defining design choice is radical simplicity: there is no database. Events live as plain .ics files and contacts as .vcf files in an ordinary folder structure, which makes backup a copy command, migration a move, and disaster recovery a matter of reading text files. The server works out of the box with no complicated setup, then grows as needed: flexible authentication (htpasswd files among other methods), per-collection authorization rules, TLS-secured connections, and a plugin system for extending storage, auth, and rights handling. Built-in limits on parallel connections, file sizes, and failed authentication attempts harden it for network exposure behind a reverse proxy. A bundled web interface handles creating and managing calendars and address books - useful since many clients cannot create collections themselves. Maintained since 2011 with 140+ contributors, GPLv3-licensed, and light enough to run on the smallest VPS or a Raspberry Pi.

Google Workspace and Microsoft 365, replaced by a platform you actually control: Nextcloud is the self-hosted digital workspace. Files is the core: file storage and sync across desktop, mobile, and web clients, with sharing, versioning, and collaboration built in. Around it, Talk provides private text chat, audio/video conferencing with screen sharing, SIP integration, and persistent voice rooms; Groupware bundles calendar, contacts, and mail with delegation support; and Office offers two collaborative suites - the Collabora-based option with deep ODF support, and Euro-Office, whose local-processing architecture delivers strong Microsoft Office compatibility and fast browser rendering with reduced server load. The Nextcloud Assistant threads AI through the platform via a context-aware sidebar, Whiteboard covers visual collaboration, Flow handles automation, and an app ecosystem of hundreds of extensions adds everything from Kanban boards to end-to-end encryption. Hub 26 brings a lighter UI with a unified app switcher and Nextcloud Governance for organizations under strict regulatory requirements. This is the flagship of data sovereignty: your files, chats, calendars, and documents live on your server, under your jurisdiction, with GDPR compliance by architecture rather than by contract.

Across personal mailboxes and business domains alike, Mail-Archiver captures, indexes, and preserves every incoming and outgoing email from multiple IMAP and Microsoft 365 accounts in a tamper-resistant archive. Connect standard IMAP servers, Microsoft 365 business tenants via Microsoft Graph, or personal Outlook and Hotmail accounts using OAuth2 device code flow without creating custom cloud app registrations. Scheduled background synchronization mirrors complete folder hierarchies automatically, while bulk tenant onboarding lets administrators import every active mailbox from a Microsoft 365 organization through a single configuration screen. When an important contract, invoice, or correspondence thread goes missing, the advanced search interface filters archived messages by sender, recipient, subject, date range, folder, and body text with instant HTML preview and direct attachment downloads. Users can import legacy MBox files or zipped EML archives, export selected messages or entire accounts, and run direct mailbox-to-mailbox migrations that copy folder trees between providers. Granular retention rules optionally purge aged messages from upstream mail servers to free quota while keeping local archive copies locked against manual deletion for compliance auditing. Multi-user access controls, OpenID Connect single sign-on, detailed activity audit logs, a scoped read-only REST API, and a Model Context Protocol endpoint allow both teams and AI assistants to query historical mail safely. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. GPL-3.0 licensed.