Matrix's flagship client, built by the protocol's creators: Element brings the decentralized open standard for real-time communication to web, desktop, iOS, and Android. Paired with a Matrix homeserver, it delivers Slack-quality team messaging where you own every message, file, encryption key, and byte of metadata. End-to-end encryption is on by default, built on Olm and Megolm - the Double Ratchet algorithm family Signal popularized, extended for large-room scalability and publicly audited by NCC Group. Messages encrypt per-device with cross-signed device verification, so even a compromised server yields nothing readable. Federation is the defining capability: like email, users on different homeservers converse seamlessly, and 30+ bridges connect Matrix rooms to Slack, Discord, WhatsApp, and Telegram, so moving to sovereign infrastructure doesn't sever contact with anyone. Rooms support threads, reactions, file sharing, and voice and video calls via Element Call. The result is digital sovereignty chosen by governments and enterprises across Europe: your data sits on your server in your jurisdiction, portable to any other Matrix host because the protocol is an open standard. Apache-2.0 licensed, with no per-user fees at any scale.

Transactions, analytics, full-text search, and vector retrieval stop needing four separate systems: MatrixOne folds them into one hyper-converged database engine that speaks the MySQL 8.0 wire protocol, so existing drivers, JDBC applications, Navicat, and BI tools connect unchanged. A single TAE storage engine serves OLTP and OLAP together, with compute and storage separated so query nodes scale independently of the data they scan. Vector columns carry IVF and HNSW indexes with L2, cosine, and inner-product distance, powering RAG and semantic search at billions scale beside your relational tables instead of in a sidecar database. Full-text indexing joins the same query, so hybrid searches combine keyword relevance and embedding similarity in one statement. Git-style version control for data lets teams clone, branch, and roll back datasets the way they already treat code, which makes experiments and audits reproducible. Streaming ingestion through Kafka connectors keeps analytical tables current, and the 4.2 line sharpens window-query performance, composite-index planning, and physical backup and restore that preserves table history. 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.

Openfire is a self-hosted XMPP server that gives your organization its own instant messaging network, with one-to-one chat, persistent group rooms, and federation to other XMPP servers, all administered from a web console. Team members connect with any XMPP client on desktop, mobile, or the web and get presence, rosters, offline message delivery, and file sharing inside conversations. Multi-user chat rooms stay available around the clock with configurable history, moderation roles, and access controls, so a support channel or project room keeps its context instead of dissolving into scattered direct messages. The plugin catalog installs from inside the admin console and adds capabilities like message archiving and compliance monitoring, a browser-based chat client, HTTP file upload, and push notifications for mobile clients. An LDAP directory or an existing database can supply users and groups, so accounts stay in sync with the directory your organization already maintains. Server-to-server federation connects your users with contacts on other XMPP domains over encrypted connections, and load balancing spreads busy deployments across multiple instances. TLS certificates, encrypted client ports, and IP-based access lists for the admin console keep the deployment under your control from the first setup wizard onward. 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.

Why rent your messaging from a corporate walled garden when Tinode runs WhatsApp-style chats, groups, channels, and calls on a server you control? Teams get one-on-one and group chats that stay in sync across web, Android, and iOS, with typing indicators, delivery and read receipts, presence, replies, forwarding, editing, pinned messages, and notes to self. Communities broadcast through read-only channels with an unlimited number of subscribers, and granular permissions decide who can read, write, or invite on each topic. Support desks welcome anonymous visitors, mark staff and verified accounts with badges, and put chatbots to work with forms and templated replies. Messages take markdown-style formatting, inline images and videos, file attachments, and voice messages. One-to-one voice and video calls run peer to peer over WebRTC, using the TURN and STUN servers you configure. Administrators block unwanted contacts on the server, attach moderation plugins over gRPC, and script the rest with a command-line tool. Attachments can sit on local disk or Amazon S3, the database can be MySQL, PostgreSQL, or MongoDB, and sharded clustering with failover scales past one server. The clients offer light, dark, and system themes, custom chat wallpapers, and translations for more than a dozen languages. 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.

Used by the Rust language community, NASA, Dropbox, and thousands of organizations worldwide with over 25,600 GitHub stars and 1,500+ contributors, Zulip is the only modern team chat app designed from the ground up for both real-time and asynchronous communication through its unique topic-based threading model where every message belongs to a named topic within a channel. This eliminates the context collapse of linear chat by letting teams follow specific conversations without scrolling through unrelated messages, resume threads days later without losing context, and catch up on missed discussions at per-topic granularity. Server 12.0 introduced end-to-end encryption for mobile push notifications, AI-powered search ranking, channel folders for workspace organization, and expanded video conferencing with Jitsi, BigBlueButton, and Zoom integration. Over 100 native integrations connect GitHub, GitLab, Jira, Sentry, PagerDuty, Travis CI, Redmine, dbt, Nextcloud, and n8n with bidirectional notifications, while LLM-driven agents access web-public channels via a standard llms.txt interface. Full-text search covers unlimited message history across all plans, code blocks render with syntax highlighting for 250+ languages, and LaTeX math expressions display inline. The REST API with typed Python and JavaScript SDKs enables custom bots, webhook integrations, and programmatic administration. Import tools migrate entire workspaces from Slack, Microsoft Teams, Mattermost, and Rocket.Chat. 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.

Blast off into productivity space with Rocket.Chat SIX, the ultimate team collaboration cosmos! Imagine a place where your messages, tasks, and projects all live in harmony, orbiting around your team's efficiency like a well-organized galaxy. This isn't just any old chat platform; it's a customizable universe where you're the master of your data domain, with the power to tweak, integrate, and innovate to your heart's content. Ready to provide stellar customer service? Engage with your clients in a way that's so contextually on-point, they'll feel like you're mind-reading across the cosmos. Plus, with a chat engine that's like a gravitational pull for user engagement, your app or website will become the center of your users' universe. And for the security-conscious space cadets, fear not! Rocket.Chat SIX is locked down tighter than a spaceship hatch, with end-to-end encryption and a buffet of deployment options to satisfy your security appetite. All this, hosted on RepoCloud, where the cost is as lightweight as zero-gravity. So why settle for a terrestrial tool when you can have a celestial experience? Rocket.Chat SIX: because your team deserves to collaborate in a universe that's light-years ahead!

Teams that cannot send messages through someone else's cloud run Mattermost - the open-core, self-hosted alternative to Slack. It provides public and private channels, threaded discussions, unlimited search history, file sharing with previews, one-to-one audio calls, and screen sharing, with desktop clients for Windows, macOS, and Linux plus iOS and Android apps. Messages support full Markdown, which suits engineering conversations with code blocks and logs. Playbooks turn repeatable processes such as incident response and release management into checklist-driven workflows with automated triggers and retrospectives. Integration is a core strength: prebuilt connectors for GitHub, GitLab, Jira, ServiceNow, and PagerDuty, plus webhooks, slash commands, bots, a REST API, and a plugin marketplace with 700+ entries - together making it a working surface for ChatOps rather than just a chat room. Playbooks add keyword and event triggers, task assignment, status broadcasting, and post-incident retrospectives, so operational knowledge is not trapped in individuals' heads. The server is a single Go binary backed by PostgreSQL, with React clients, released monthly under MIT license and deployable fully air-gapped - which is why governments and defense organizations run it inside closed networks, and why the same control applies to any team with confidentiality requirements. The compiled Team Edition is free for unlimited users with no message history cutoff, so costs stay flat as the team grows.

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.

Revolt gives communities the full Discord experience without ads, behavioral tracking, or subscription fees: servers with text and voice channels, direct messages, group conversations, roles, bots, and custom emoji at zero cost per user. The Rust microservices backend splits responsibilities across Delta for REST API and authentication, Bonfire for persistent WebSocket real-time event delivery, Autumn for file upload routing to MinIO S3-compatible object storage, and January for link preview proxy and embed generation. Voice chat operates through LiveKit with WebRTC audio streaming supporting multiple concurrent participants per channel. Server administrators configure hierarchical role-based permissions at the server, channel, and per-role level, controlling who can send messages, manage channels, kick members, and access moderation tools. Text channels support Markdown formatting, custom emoji, file attachments up to 20 MB, GIF search via Tenor integration, and message reactions. The bot API enables automated moderation, entertainment, and custom workflow integration with community-maintained libraries available in JavaScript, Python, and Rust. The TypeScript and Solid.js web frontend provides a responsive interface with theme customization. Docker Compose deployment spins up the complete stack including MongoDB for message and user storage, Redis for caching, and MinIO for attachments, providing complete data sovereignty over all conversations and files. 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.

Fluxer gives friends, gaming groups, and private communities their own self-hosted instant messaging and VoIP platform that replaces Discord with private text channels, voice rooms, video calls, and screen sharing. Members can chat one-on-one in direct messages, form multi-person group conversations, or organize large community servers into categorized text and voice channels with threaded replies, reactions, and typing indicators. When a conversation moves to voice, participants can join low-latency audio and video rooms from multiple devices simultaneously, share application windows or full screens, and rely on built-in noise suppression and echo cancellation for clear calls. Rich media support allows users to share file attachments, preview embedded links, search animated GIFs through KLIPY, and upload custom community emojis and stickers. Server administrators control access through role-based permission hierarchies, member timeouts, kicks, bans, and detailed moderation audit logs that track every configuration change across the community. Integrated full-text search lets members quickly locate historical messages, code snippets, and shared files across every channel they can access. 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.

Think of it as a team messaging platform where every feature beyond core chat is a plugin you can install or remove, inspired by VS Code's extension model but applied to real-time communication. The Moleculer microservice backend scales horizontally across nodes while Socket.io delivers instant message synchronization with text, images, files, mentions, reactions, and rich Markdown formatting. Available plugins provide LiveKit video conferencing, collaborative drawing boards, task management panels, end-to-end encryption, custom themes, and third-party push notification reception without touching core code. Groups use a two-level space system with customizable panel layouts arranged through drag-and-drop, while role-based access control enforces fine-grained permissions across the organization. The Open Platform exposes OAuth for single sign-on across connected applications and a Bot API enabling bidirectional message processing between Tailchat and external services via HTTP requests. Multi-platform clients cover web, Electron desktop with screenshot capabilities, and mobile apps with native push. Docker Compose deployment bundles MongoDB for persistence, Redis for caching and transport, and MinIO for S3-compatible file storage. Deploy on RepoCloud with a dedicated VPS for persistent team infrastructure under the Apache 2.0 license.

Haven gives your community a private chat server with voice calls, screen sharing, and end-to-end encrypted direct messages where friends join via invite link in their browser without installing apps or creating third-party accounts. Real-time messaging supports image uploads via paste and drag-drop, emoji reactions, replies, threads, typing indicators, @mentions with autocomplete, and inline GIF search through Tenor or GIPHY. Peer-to-peer WebRTC voice chat includes per-user volume sliders, mute and deafen controls, talking indicators, and screen sharing with picture-in-picture mode. Direct messages use ECDH P-256 key exchange with AES-256-GCM symmetric encryption where private keys never leave the browser, ensuring not even the server operator can read them. Twenty-plus visual themes with stackable effects including CRT scanlines, Matrix Rain, Cyberpunk Text Scramble, Snowfall, and Campfire Embers let users personalize the experience with configurable intensity sliders. Rich Presence integration shows what members are playing or listening to via Last.fm, Steam, and Spotify. A built-in bot API supports webhooks and custom slash commands, while Discord history import preserves channels, threads, forums, reactions, pins, and avatars. The Node.js server deploys via Docker Compose or a single batch file that auto-handles dependencies, SSL certificates, and configuration. 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.

On game night Sharkord carries voice, webcams, and screen sharing, and on Monday morning it carries the team's threaded chat, all from one server you control. For the gaming crowd, voice rooms offer noise suppression, echo cancellation, webcams up to 2160p, and screen sharing in VP8, VP9, H264, or AV1, with optional simulcast layers for slow viewers. An experimental Bridge app keeps push-to-talk and mute hotkeys working with a game in focus, and plugins add a music bot or a soundboard. For a family group, invite links can carry a role, a use limit, and an expiry, and replies, reactions, custom emoji, pins, and direct messages keep conversation casual, with uploads up to 2 GB each. For a small team, text channels sit in categories with threads, mentions, and search, roles stack with per-channel permissions for private rooms, and OpenID Connect sign-in works with Authentik, Keycloak, Zitadel, Entra ID, or Google Workspace. Admins cap storage per user or role and can sign upload URLs. There is no premium tier, no member cap, no ads, and no tracking, and a built-in marketplace installs plugins in one click. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Your team chat can be one executable on your own server: Campfire Rust runs rooms, direct messages, attachments, and search as a single binary that replaces the whole Ruby, Puma, Redis, Resque, and Thruster stack. Create rooms with access controls for projects, departments, or a private board discussion, and keep direct messages beside them for quick questions. File attachments arrive with previews, mentions pull the right person into a thread, and search finds the decision someone made months ago. Web Push notifications reach browsers and phones, so a quiet room still finds its people when it matters. Chatbots connect through a simple HTTP API for sending and receiving messages and attachments, which makes Campfire a home for build alerts, deploy notices, and support pings. Existing Campfire installs upgrade in place because the Rust binary reads the same SQLite database, storage layout, and signed cookies, with no data migration and no mass sign-out. Automatic TLS with Let's Encrypt certificates, HTTP/2, and Action Cable-compatible WebSockets are built in, and the whole system works on air-gapped networks that never touch the internet. Run it as your primary chat, as a backup for the day a hosted service goes down, or as a walled garden for executives and events. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Chitchatter is a browser-based chat room for text, voice, video, screen sharing, and file transfers that exists only while its members are connected and keeps no record of what was said. Every visit starts with a random room name generated on your device, a UUID or a readable passphrase, and you invite people with the link or a QR code. Public rooms admit anyone with the link; private rooms also require a matching password. Messages support Markdown, multiline text, and code blocks, and clicking a name opens a direct conversation. Newcomers to public rooms receive the earlier conversation from peers already there, and typing indicators show who is writing. Start an audio or video call, share your screen to walk a relative through a settings problem, or hand over a file of any size, encrypted before it leaves your browser. Public-key checks verify each peer automatically, with a green lock marking everyone who passes and an icon showing whether the link is direct or relayed. Embed a room in any web page with an iframe or a web component that takes a room name, user name, and color mode. Light and dark themes are built in, and notifications and sounds announce new messages while you work in another tab. Close the tab and the transcript disappears. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. GPL-2.0 licensed.

A single ejabberd node carries chat, device telemetry, voice calls, and federated messaging at once, because the same Erlang server speaks XMPP, MQTT, SIP, and Matrix over one authentication, storage, and clustering layer. Users get standards-based instant messaging with group chats, message archives, publish-subscribe, message carbons, push notifications, and OMEMO encryption, and your server federates with the global XMPP network out of the box. Devices publish and subscribe through the built-in MQTT broker on TCP or WebSocket transports, sharing accounts and access rules with your chat users instead of needing a second broker. Voice and video calls route through the integrated SIP gateway and STUN/TURN support, so WebRTC clients get signalling and media relay from the same deployment. Matrix support bridges federated rooms into the same infrastructure, letting two decentralised ecosystems interoperate without a separate bridge stack to babysit. Clustering with consistent hashing scales a deployment across nodes, and a single node is rated at two million concurrent sessions for very large communities. Operators manage everything from the web admin and command line, with SQL or Mnesia storage, LDAP authentication, and virtual hosting for multiple domains on one server. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. GPL-2.0 licensed.

With over 7,500 GitHub stars and 140 contributors, Matterbridge is the Go-powered chat bridge that connects over 20 messaging platforms through a single TOML configuration file, letting teams communicate across platform boundaries without forcing anyone to switch applications. The gateway architecture routes messages bidirectionally between any combination of Discord, Slack, Telegram, Matrix, IRC, Mattermost, Microsoft Teams, XMPP, Rocket.Chat, Nextcloud Talk, Keybase, Mumble, Twitch, WhatsApp, VK, Gitter, Zulip, ssh-chat, and Harmony, with transparent username and avatar spoofing so bridged messages appear native on each platform. Message edits and deletes propagate across bridges, file attachments and inline images transfer between protocols, threading and reply context is preserved where platforms support it, and private group bridging enables confidential cross-platform conversations. Multiple independent gateways can run simultaneously, each bridging different channel sets with different protocol combinations. The REST API enables third-party integrations and custom bridges without modifying the Matterbridge codebase, while the tengo scripting engine allows inline message transformation and filtering. Game chat support bridges Minecraft and Counter-Strike server chat into messaging platforms. Deployment runs as a single static Go binary with zero dependencies, or as the official Docker image with the configuration file mounted as a volume. 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.

MiroTalk P2P gives your team browser meeting rooms with video, screen sharing, and chat, where the media travels directly between participants instead of through a rented cloud. Create a room, send the link, and guests join from any modern browser with nothing to install and no account to create. Calls carry video at high frame rates, and anyone can share a full screen, one window, or a browser tab to walk through documents and slides. The built-in recording captures screen, camera, and audio in the browser, ready to download and pass along after the meeting. Chat supports Markdown formatting and emoji, and the room also packs a collaborative whiteboard, a shared text editor, live polls, and breakout rooms. Files move between participants inside the call, and speech recognition plus voice commands keep hands free during long sessions. Hosts lock rooms with passwords, hold arrivals in a lobby, and require approval before strangers wander in. Sign-in through OIDC, per-room JWT credentials, and host protection controls keep recurring meetings behind your own identity provider. A full REST API creates rooms from your own tools, Slack and Mattermost commands start calls from chat, and an iframe embed drops meetings into existing pages. The interface speaks 133 languages, and an optional ChatGPT assistant joins rooms to answer questions in the conversation. 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.