Marketing campaigns and transactional mail from one open-source platform: Notifuse is a modern, self-hosted alternative to Mailchimp, Brevo, and Klaviyo without per-email or per-contact pricing. Built with Go and React on PostgreSQL, it separates concerns cleanly: a drag-and-drop visual builder composes responsive templates from MJML components with Liquid variables like {{ contact.first_name }} and per-template version history; campaigns add A/B testing across subject lines, content, and send times; and a REST transactional API serves application-triggered mail. Delivery routes through your choice of provider - Amazon SES, Mailgun, Postmark, SendGrid, SparkPost, Mailjet, or plain SMTP - with multi-provider failover. Contacts carry custom fields and a full activity timeline (messages, profile changes, webhook events), and real-time segmentation builds dynamic rules over properties, activity, and subscriptions. Event-driven automations create behavioral sequences, a notification center gives recipients self-service preference management, and an S3-compatible file manager handles images with CDN delivery. Multi-tenant workspaces with isolated databases and custom domains suit agencies. Open and click tracking report engagement in real time.

Movie night should not depend on everyone pressing play at the same second; SyncWatch runs your own watch-party server so friends in different places watch the same frame together. The host controls play, pause, seeking, and playback speed for the whole room, and late joiners or drifting clients are corrected back to the shared position automatically. You build the program from uploads or direct HTTPS media links, with subtitles, audio, images, and documents handled in the same library. Rooms can be permanent or temporary, protected by passwords and member limits, with host, admin, and permission-group control over who may operate playback. Between scenes, people talk through public and private chat, on-screen danmaku comments, emoji, voice messages, or full-room voice. Anyone can share a browser tab, window, desktop, or phone screen into the room, so a clip, a game, or a presentation becomes the shared screen. The server also keeps friends, notifications, online presence, bans, registration approvals, and an operations log, so a private community can run itself without a platform account. Uploaded media is analyzed and thumbnailed automatically, with browser-compatible versions generated for awkward formats. Backups, data export, a recycle bin, mail verification, and network diagnostics round out the admin side. 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.

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.

With DSpace, a library or research office can give every thesis, journal article, and dataset its own permanent web address, a searchable metadata record, and files visitors download from the archive. Content sits in a tree of communities and collections, and each collection decides who may deposit and how many review steps follow; reviewers accept a submission or reject it with a note that sends it back to the author. Embargoes hold files back until a set date, access policies limit other files to chosen groups, and sign-in works through LDAP, Shibboleth, SAML, OpenID Connect, or ORCID. Search covers metadata and the extracted full text of uploaded files, facets narrow the results, and browse pages sort by title, issue date, author, or subject. Editors can correct a published item through the submission form. Administrators inspect an audit trail and rewrite homepage news from an admin form. Entity types for people, organizations, projects, journals, and datasets link each publication to the work behind it, and DOIs can be registered through Crossref. Optional settings let authors keep an email address private on their researcher profile and download their own restricted files. Usage reports count visits, downloads, and top countries per item. REST, OAI-PMH, SWORD, and Google Scholar metadata connect the archive to harvesters, deposit tools, and search engines. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. BSD-3-Clause licensed.

Mail-in-a-Box turns a single Ubuntu server into a fully functional email system with one setup command, installing and configuring Postfix for SMTP, Dovecot for IMAP, Roundcube for webmail, and Z-Push for Exchange ActiveSync push notifications in an automated sequence that would take days to replicate manually. The DNS server auto-configures the full suite of email authentication records: SPF, DKIM, DMARC, DNSSEC with DANE TLSA, MTA-STS, and SSHFP. Getting all of these right is what separates email that lands in inboxes from email that lands in spam, and most manual installations never achieve the complete set. Nextcloud integration adds CardDAV contact sync and CalDAV calendar sharing across devices. Let's Encrypt certificates provision and renew automatically for every hosted domain. The web control panel manages users, aliases, custom DNS records, and automated backups, protected by TOTP two-factor authentication. Daily health checks verify that services run correctly, ports remain open, TLS certificates stay valid, and DNS records resolve properly, alerting you before delivery problems develop. Multiple domains and users operate from one installation with internationalized domain name support. Built-in HTTPS static site hosting uses the TLS infrastructure already in place. Runs on a dedicated RepoCloud VPS with guaranteed resources, root SSH, and browser serial console for complete email sovereignty. CC0 public domain licensed.

Running your own mail server usually means assembling five services and praying over DNS records; LanQin Email ships the whole stack in one container. Readers switch between mailboxes, search, label, star, and file messages into folders, then compose with a rich-text editor that handles fonts, colors, code blocks, attachments, emoji, and scheduled sending. Contacts, signatures, inbox rules with automatic forwarding, sender blacklists, and mail statistics make it a daily client rather than a demo. Administrators run the postal side from the same panel: add domains and generate DKIM keys, follow the DNS record checklist the system verifies for you, create mailboxes, set delivery aliases and catch-all addresses, and audit every message on the server. Accounts sign in with passwords or OAuth single sign-on, protected by TOTP two-factor codes and bot checks, while permission groups cap attachment size, sending rate, and mailbox count per user. Users can even request their own mailbox and wait for approval instead of filing a ticket. For programs, an Open API with bearer tokens sends mail idempotently and reports delivered, bounced, complained, rejected, and deferred events back through webhooks. External Gmail and Outlook accounts can be aggregated over IMAP, and a client-configuration page shows every IMAP, POP3, and SMTP setting in one place. A multi-container layout remains for debugging the stack piece by piece. 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.

With over 20,000 GitHub stars and adoption by companies building everything from telehealth platforms to AI voice agents, LiveKit is the most widely deployed open-source real-time communication server available. The Go-based Selective Forwarding Unit handles hundreds of concurrent participants per node with adaptive bitrate streaming, simulcast layers, SVC codec support for VP9 and AV1, and end-to-end encryption. Client SDKs span JavaScript, Swift, Kotlin, Flutter, React Native, Rust, Python, Unity, and ESP32 embedded devices, while server-side APIs cover Node.js, Go, Ruby, Java, Python, Rust, PHP, and .NET. The Agents framework enables building AI-powered voice and video applications — real-time speech-to-text, LLM-driven conversations, and computer vision pipelines — running as server-side participants in any room. Egress records sessions to S3-compatible storage or streams to RTMP endpoints, while Ingress pulls external feeds from OBS via RTMP, WHIP, or SRT into LiveKit rooms. The SIP bridge connects traditional telephony to WebRTC rooms for hybrid conferencing. JWT-based authentication, webhook notifications, room-level moderation APIs, and selective subscription give operators granular control. Deploy as a single binary for development, Docker Compose for production single-node, or Kubernetes with the official Helm chart for distributed multi-region clusters using Redis for state coordination. 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.

Workplace and Yammer's pattern on your own server, with GDPR compliance by construction rather than contract: HumHub is an open-source enterprise social network from Germany. Built in PHP on Yii2, it organizes everything around four concepts. Users get rich profiles with follows and interactions. Spaces are the structural unit - rooms for departments, projects, events, or clubs, with per-Space permissions, notification settings, and email summaries, and operators can auto-map users into the right Spaces. Content covers posts, wiki pages, photos and video, events, and tasks, with multi-level comments, versioning, archiving, moderation reporting, and filterable full-text search across everything. Modules make it a platform: roughly 80 install-and-activate extensions including Calendar, Wiki, Polls, Tasks, Gallery, News, direct-message Mail, OnlyOffice document editing, Advanced LDAP, SAML and JWT SSO, a RESTful API, mass user import, Translation Manager, and a Theme Builder with custom pages - every one optional and toggleable at runtime. That module economy is why HumHub serves such varied deployments: corporate intranets, city governments, universities, political parties, and nonprofits all configure the same core differently. Requirements are a plain LAMP stack - PHP 8.1+ and MySQL/MariaDB - making it one of the easiest community platforms to operate long-term.

Decisions that scatter across email threads and chat scrollback get one home in Loomio, where a group discusses a question, votes, and publishes what it decided. Every decision starts as a thread with context, comments, @mentions, reactions, tags, and attachments, and tasks inside it carry assignees and emailed due-date reminders. Proposals ask for a defined response plus an optional written reason, using sense check, advice, consent, or consensus templates. Polls handle simple choices, scores, dot voting, ranked choice, meeting-time availability, and multi-winner STV elections. Coordinators set a participation quorum, require a vote share, weight votes, limit voting to appointed delegates, or hide results until close with anonymous voting. Groups nest subgroups, pick Open, Closed, or Secret visibility, and admit members freely, by request, or by invitation. People reply to discussion emails and catch up through a daily digest, and webhook integrations post invitations and outcomes to Slack, Discord, Microsoft Teams, Matrix, and Mattermost. Published outcomes stay searchable, and groups export CSV, HTML, or JSON and print threads to PDF. Comments translate on request, the interface is available in 24 languages, and a user API, server API, and webhooks connect other tools. 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.

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.

Stoat delivers a complete Discord-like community chat experience that organizations can self-host on their own infrastructure with full data ownership. The platform provides text channels organized in categories, real-time voice calls powered by LiveKit, file sharing with automatic media proxying, custom emoji support, bot framework, GIF search, server invites, and granular role-based permissions — all wrapped in a polished web UI that feels immediately familiar to Discord users. The architecture separates concerns across dedicated Rust binaries handling the REST API, WebSocket real-time events, file storage with S3-compatible backends, push notifications, and media proxying, backed by MongoDB for persistence and Redis for caching. Web, desktop, and mobile clients connect through the same API, ensuring consistent experience across platforms. Unlike federated alternatives such as Matrix, Stoat provides a single-server deployment model focused on the Discord-style community experience: server invites, channel categories, member management, and an invite-first onboarding flow that communities expect. The Docker Compose deployment stack handles all microservices with Caddy providing automatic TLS via Let's Encrypt. 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.

"Forget about bouncers" became a real sentence because of The Lounge: a Node.js web IRC client that holds persistent connections to your networks 24/7, logging everything while you sleep, so closing the browser tab never means missing a message or losing your place in a channel. Open it again from any device - desktop, phone, tablet - and you resume exactly where you left off, with full history synchronized. Because it combines bouncer and client in one process, the experience feels like a modern chat app rather than 1990s infrastructure: push notifications for highlights and private messages (with self-generated VAPID keys, so even Web Push needs no third-party service), automatic link previews, inline file and image uploads, and full IRCv3 protocol support. It installs as a progressive web app from any modern browser, so phones get a native-feel client without an app store. Multi-user support means one instance serves your whole team or community, each user with their own networks and history, and LDAP integration ties into existing authentication. A public mode alternatively serves as an open, registration-free web chat for events or support channels. MIT-licensed, born as a fork of Shout, and a fixture of self-hosting stacks since.

Powering over 496 instances with more than 35,000 monthly active users and 26,500 communities, Lemmy has established itself as the leading open-source, federated link aggregation platform in the Fediverse. Built entirely in Rust for memory-safe, high-performance server operation, Lemmy enables anyone to run their own Reddit-style community that automatically connects with every other Lemmy instance — and compatible ActivityPub platforms like Mastodon, PieFed, and Kbin — through standardized federation protocols. Users create and subscribe to topic-based communities, submit posts containing text, links, or images, engage through threaded comment discussions, and shape content visibility through upvote/downvote mechanisms. Instance administrators retain full control over moderation policy, federation allowlists and blocklists, site appearance, and user registration settings, while community moderators can sticky posts, lock threads, ban users, and maintain public moderation logs for transparency. The platform supports private messaging between users, email notifications, RSS and Atom feed generation for every community, comprehensive internationalization with dozens of language packs, custom emoji support, and both light and dark themes through a clean mobile-responsive interface. Deployment is straightforward with official Docker Compose configurations and Ansible playbooks, backed by a PostgreSQL database with pict-rs for image hosting. Lemmy's Rust backend consistently benchmarks among the most efficient Fediverse server implementations, enabling small VPS instances to serve thousands of users. 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.

One Janus installation can host a video meeting in one session, stream a camera feed in another, and bridge a browser call into a telephone network in a third, because Janus is a general-purpose WebRTC server whose work is done by interchangeable plugins. The VideoRoom plugin publishes each participant's streams to everyone else in the room with simulcast and viewport selection, so a class or team call adapts quality per viewer instead of forcing one bitrate on all. Streaming mounts live or prerecorded sources, including RTSP cameras and RTP feeds, and hands them to any number of WebRTC viewers, while AudioBridge mixes voices into conference rooms with recording and signed-token access. SIP and NoSIP plugins register with existing VoIP infrastructure and place or receive calls, translating between WebRTC media and telephone audio so a web page can ring a desk phone. Record&Play captures publisher streams to files you can replay through the same server, TextRoom adds data-channel chat rooms, and Lua or JavaScript plugins let you script custom media logic without recompiling the core. Applications talk to Janus over HTTP or WebSocket APIs, with RabbitMQ, MQTT, and NATS transports for bus-driven deployments, and event handlers report session activity to your monitoring stack. 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.

With 3,300+ GitHub stars, 200+ releases, and v1.77 shipping in July 2026, Frappe CRM delivers enterprise CRM capabilities without per-seat licensing costs that plague Salesforce and HubSpot deployments. The Python backend running on Frappe Framework v15/v16 with MariaDB and Redis pairs with a Vue 3 frontend using Pinia state management, Vue Router, and the Frappe UI component library styled with Tailwind CSS v3. All-in-one lead and deal pages consolidate activities, comments, notes, tasks, call logs, and email history into a single scrollable view while the drag-and-drop Kanban board provides visual pipeline tracking across configurable stages. Built-in Twilio integration enables click-to-call with recording directly from deal pages, Exotel routes calls through agent mobile phones, and WhatsApp messaging connects via the Frappe WhatsApp module for conversational sales. A visual field layout editor lets non-technical users customize CRM forms, sidepanels, and grid views with real-time drag-and-drop without writing code. The Service Level Agreement engine tracks first-response and rolling-response times against configurable policies with automatic escalation. Meta integration captures leads from Facebook and Instagram ad campaigns directly into the pipeline. ERPNext connectivity extends CRM into invoicing, accounting, inventory, and purchasing with native data flow. Docker Compose deployment with a single command provisions a production-ready instance. 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.

With over 7,100 GitHub stars and 200 contributors since 2016, Mailu has become one of the most popular self-hosted email solutions, delivering a complete production-ready mail server stack as pre-configured Docker containers that eliminate weeks of manual setup. The platform bundles Postfix for SMTP and Submission with auto-configuration profiles for Thunderbird, Outlook, and mobile clients, Dovecot for IMAP and POP3 with full-text search across email attachments, Rspamd for intelligent spam filtering with auto-learn Bayesian classification, greylisting, SPF and DMARC validation, and ClamAV for antivirus scanning of attachments with configurable malicious file blocking. The web administration interface provides global admin controls, per-domain delegation, user quota management, domain aliases, custom routing rules, and announcement capabilities. Users access self-service features including aliases, auto-reply, auto-forward, fetched accounts from external mailboxes via fetchmail, and Sieve filter management through ManageSieve. Security features include enforced TLS on all connections, automatic Let's Encrypt certificate provisioning, outgoing DKIM signing, DANE and MTA-STS support for transport security, and Snuffleupagus PHP hardening for the web interface. The setup wizard at setup.mailu.io generates complete Docker Compose configurations tailored to specific deployment requirements. All components are free and open-source software with zero proprietary dependencies and no tracking. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Companies with privacy and security concerns about piping customer conversations through Intercom or Zendesk run Papercups - open-source live customer chat. The stack is a deliberate strength: an Elixir/Phoenix API over PostgreSQL, with real-time messaging powered by Phoenix Channels and Presence - the same BEAM foundation trusted by Discord and PagerDuty for fault-tolerant, low-latency messaging. Customers see a customizable chat widget that embeds in any site as an HTML snippet, a React component, or even inside React Native apps, with configurable colors, greetings, and away messages. Your team sees a dashboard for managing conversations - close, assign, and prioritize - with Markdown and emoji in replies. The killer workflow is the reply-channel integration: connect Slack or Mattermost and every customer conversation becomes a synced thread your team answers without leaving the tool they already live in, with two-way message syncing handled by webhooks. Email and SMS channels extend intake beyond the widget, an analytics dashboard tracks communication patterns, and the Storytime feature adds real-time screen sharing to watch users navigate while you help them. A documented API supports fully custom chat UIs in Svelte, Flutter, or Vue. MIT-licensed and GDPR-conscious - customer data stays in your PostgreSQL.

Build a voice AI agent that answers calls, qualifies leads, books appointments, and transfers to a human when needed, all from a drag-and-drop workflow builder in your browser. Dograh ships as a Docker Compose stack (API, web UI, Postgres, Redis, MinIO) that you self-host on any Linux server with automatic HTTPS provisioning via Let's Encrypt. The visual workflow builder lets you design multi-turn conversation flows by connecting nodes for greetings, intent classification, tool calls, and handoffs; describe your use case in plain English and the platform generates the LLM prompt and node graph for you. Connect your own speech-to-text, LLM, and text-to-speech providers (OpenAI, Anthropic, Gemini, ElevenLabs, Deepgram, local Whisper, Kokoro, or any OpenAI-compatible endpoint) or use the built-in Speech-to-Speech mode with Gemini Flash Live and GPT-Realtime-2 for sub-200ms latency. Telephony plugs in through Twilio, Vonage, Vobiz, or Cloudonix for inbound and outbound calling, with live agent transfer when the conversation needs a human. Webhook tool calls connect to Salesforce, HubSpot, Google Calendar, Cal.com, or any REST API without writing orchestration code. The ClonedVoice feature mixes real human voice recordings for high-frequency phrases with neural TTS fallback for dynamic content, cutting costs while improving caller trust. A built-in MCP server lets AI coding agents like Claude Code or Cursor design, test, and edit workflows through natural language. Deploy on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. BSD 2-Clause licensed.