Communicatie & chat

All-in-one mail server with JMAP, IMAP4, and SMTP support and a wide range of modern features.

Scalable MQTT broker. Connect 100M+ IoT devices in one single cluster, move and process real-time IoT data with 1M msg/s throughput at 1ms latency.

The most private and secure chat and applications platform - now with double ratchet E2E encryption.

Mail server suite based on Dovecot, Postfix and other open source software, that provides a modern Web UI for administration.

Collaboration suite built to enable collaboration, synchronizing changes to documents in real time.

Realtime collaborative markdown notes on all platforms, formerly known as CodiMD and HackMD CE.

File storage, syncing, sharing, and collaboration with real-time editing, permission management, and desktop/CLI clients.

Simple, secure, fast real-time video conferences up to 4k and 60fps, compatible with all browsers and platforms.

Simple, secure, scalable real-time video conferences up to 4k, compatible with all browsers and platforms.

Complete and fully featured mail server for use by websites & web servers.

Production-ready fullstack but simple mail server (SMTP, IMAP, LDAP, Antispam, Antivirus, etc.) running inside a container. Only configuration files, no SQL database.

POP/IMAP/SMTP/Caldav/Carddav/LDAP exchange gateway allowing users to use any mail/calendar client with an Exchange server, even from the internet or behind a firewall through Outlook Web Access.

XMPP instant messaging server.

Bookmark and archive manager to store your useful links.

Email archiving server that syncs from IMAP accounts, indexes emails for full-text search, and provides a REST API. No external database required, includes WebUI with multi-account support.

Highly customizable online editor providing collaborative editing in real-time.

📞 Open-source, self-hosted WebRTC click-to-call solution for websites. Add a video Call-Me button and let visitors instantly connect with your team through browser-based video communication. Ideal for customer support, sales, consultations, and remote assistance.

XMPP server implementation in Java.

Communications platform that puts data protection first (alternative to Gitter.im and Slack).

短信转发器——监控Android手机短信、来电、APP通知，并根据指定规则转发到其他手机：钉钉群自定义机器人、钉钉企业内机器人、企业微信群机器人、飞书机器人、企业微信应用消息、邮箱、bark、webhook、Telegram机器人、Server酱、PushPlus、手机短信等。包括主动控制服务端与客户端，让你轻松远程发短信、查短信、查通话、查话簿、查电量等。（V3.0 新增）PS.这个APK主要是学习与自用，如有BUG请提ISSUE，同时欢迎大家提PR指正

Zulip is a powerful, open source group chat application.

High performance, self-hosted newsletter and mailing list manager with a modern dashboard.

Open-source feature management platform

Open source voice AI platform. Self-hosted alternative to Vapi and Retell. On Prem, BYOK across Speech to Speech or LLM/STT/TTS, with a visual workflow builder, MCP native and telephony support.

Peer-to-peer chat app that is serverless, decentralized, and ephemeral.

Real-time cam-2-cam video calls & screen sharing, end-to-end encrypted, to embed in any website with a simple iframe.

High-Performance server for NATS.io, the cloud and edge native messaging system.

Realtime kanban board for workgroups (alternative to Trello).

Open source email alias solution to protect your email address. Comes with browser extensions and mobile apps.

Apache Kafka® running on Kubernetes

Markdown note-taking web application designed for simplicity.

A modern, feature-rich, databaseless flat-file wiki platform.

🛠 Open-source, self-hosted WebRTC SaaS platform and video meeting scheduler. Provide user accounts, dashboards, meeting scheduling, invitations, and centralized access to MiroTalk services. Build your own branded video meeting platform on infrastructure you control.

Apache RocketMQ is a cloud native messaging and streaming platform, making it simple to build event-driven applications.

Apache Pulsar - distributed pub-sub messaging system

🧑‍🚀 Authentication and authorization infrastructure for SaaS and AI apps, built on OIDC and OAuth 2.1 with multi-tenancy, SSO, and RBAC.

Fast, highly extensible, and event driven SMTP server.

✉️ Teaching an Old Dog New Tricks -- IRC: #neomutt on irc.libera.chat

Feed reader for your email accounts.

Instant messaging platform. Backend in Go. Clients: Swift iOS, Java Android, JS webapp, scriptable command line; chatbots.