Communication

Loom

Communication

Async video messaging for work

Hound CI

Communication

Comments on style violations in GitHub pull requests. Supports Coffeescript, Go, HAML, JavaScript, Ruby, SCSS and Swift.

See how ChatGPT, Perplexity & Gemini actually read your site

Caprine

Communication

Third-party privacy-focused Facebook Messenger app. ![Open-Source Software][OSS Icon] ![Freeware][Freeware Icon]

Cursor

Communication

AI code editor with autocomplete, chat, and coding agent features. ![Freeware][Freeware Icon]

HuggingChat

Communication

Open-source AI chat by Hugging Face

Run your entire creative pipeline from one chat agent

SimpleX Chat

Communication

The most private and secure chat and applications platform - now with double ratchet E2E encryption. AGPL-3.0 Haskell

Quassel IRC

Communication

Distributed IRC client, meaning that one (or multiple) client(s) can attach to and detach from a central core. ([Source Code](https://github.com/quassel/quassel)) GPL-2.0 C++

Plug Google Ads, Meta & LinkedIn into your AI chat. Free

Litmus

Communication

an email campaign creation platform that, amongst other things, lets you see how HTML emails will appear in a wide variety of email clients.

Your AI chats, saved as Markdown locally with no cloud

Turn codebases into a clean file for Claude and ChatGPT

Turn one-off chats into persistent, usable apps

Run Apple Search Ads by Chatting with AI

Optimize your website for ChatGPT, Perplexity & AI Search

See how much traffic your website gets from ChatGPT

BYOSMTP email platform — enterprise features from ₹1,199/mo

Apprise

Communication

Apprise allows you to send a notification to almost all of the most popular notification services available to us today such as: Telegram, Discord, Slack, Amazon SNS, Gotify, etc. MIT Python/Docker/de

Reviewdog

Communication

A tool for posting review comments from any linter in any code hosting service.

Turn YouTube comments into channel growth, in 45 seconds!

Mailpile

Communication

A modern, fast web-mail client with user-friendly encryption and privacy features.

Check if ChatGPT and AI search engines understand your brand

Generate edited, sound-designed videos via chat

Chat with your spreadsheet, edit cell with natural language

Monitor which ChatGPT ads show up on your queries

Discord

Communication

Voice, text, and community chat platform.

AsmBB

Communication

Fast, SQLite-powered forum engine written in ASM. ([Source Code](https://asm32.info/fossil/asmbb/index)) EUPL-1.2 Assembly

Rank #1 on Google & ChatGPT on full autopilot

Local-first AI memory bridge between browser chats and IDEs

Capture AI chats into your knowledge base

PaletteBrain

Communication

Access the power of ChatGPT across all your Mac applications with the press of a shortcut.

irssi

Communication

IRC chat client.

PingMe

Communication

Send messages/alerts to multiple messaging platforms & email.

cmatrix

Communication

Scrolling 'Matrix'-like screen.

linty fresh

Communication

Parse lint errors and report them to Github as comments on a pull request.

mail-archiver

Communication

Web application for archiving, searching, and exporting emails from multiple accounts (IMAP, M365 or Import). Featuring folder sync, attachment support, mailbox migration and a dashboard. GPL-3.0 Dock

Tinode

Communication

Instant messaging platform. Backend in Go. Clients: Swift iOS, Java Android, JS webapp, scriptable command line; chatbots. ([Demo](https://sandbox.tinode.co/), [Source Code](https://github.com/tinode/

SyncTube

Communication

Lightweight and very simple to setup CyTube alternative to watch videos with friends and chat. MIT Nodejs/Haxe

Atomic Chat

Communication

Open-source AI chat client for local and cloud models with MCP support. [![Open-Source Software][OSS Icon]](https://github.com/AtomicBot-ai/Atomic-Chat)

kirc

Communication

Tiny IRC client.

Spark

Communication

Fast email client. For both Mac OS and iOS.![Freeware][Freeware Icon]

LangLint

Communication

Automated translation platform for code comments and docstrings across 20+ file types. Eliminates language barriers in international software collaboration. Supports 100+ language pairs with syntax pr

Add voice and video calling via your coding agent

Check what ChatGPT says about your brand, from your desktop

Candy

Communication

Multi user XMPP client written in Javascript.

Create, manage, and measure your ChatGPT ad campaigns

Picsart's power right from your AI chat box

AI Designer Team. Cancel Canva, ChatGPT and Notion.

iRedMail

Communication

Full-featured mail server solution based on Postfix and Dovecot. ([Source Code](https://github.com/iredmail/iRedMail)) GPL-3.0 Shell

Lets-Chat

Communication

A self hosted chat suite written in Node.

Generate production-ready files directly in your chat

Talkyard

Communication

Create a community, where your users can suggest ideas and get questions answered. And have friendly open-ended discussions and chat (Slack/StackOverflow/Discourse/Reddit/Disqus hybrid). ([Demo](https

Rank your brand in ChatGPT, Gemini, and AI answers

10 seconds – all posts, reviews, push notifications

Track where AI mentions your SaaS across Reddit and forums

Countly Community Edition

Communication

Real time mobile and web analytics, crash reporting and push notifications platform. ([Source Code](https://github.com/Countly/countly-server)) AGPL-3.0 Nodejs/Docker

Textual

Communication

Internet Relay Chat (IRC) client. [![Open-Source Software][OSS Icon]](https://github.com/Codeux-Software/Textual) [![App Store][app-store Icon]](https://apps.apple.com/us/app/telegram/id747648890?plat

Dovecot

Communication

IMAP and POP3 server written primarily with security in mind. ([Source Code](https://github.com/dovecot/core)) MIT/LGPL-2.1 C/deb

Ech0

Communication

Lightweight federated publishing platform focused on personal idea sharing (documentation in Chinese). ([Demo](https://memo.vaaat.com/), [Source Code](https://github.com/lin-snow/Ech0)) AGPL-3.0 Docke

Conduit

Communication

A simple, fast, and reliable chat server powered by Matrix. ([Source Code](https://gitlab.com/famedly/conduit)) Apache-2.0 Rust

Notifo

Communication

Multichannel notification server with support for Email, Mobile Push, Web Push, SMS, messaging and a javascript plugin. MIT C#

Element

Communication

Fully-featured Matrix client for Web, iOS & Android. ([Source Code](https://github.com/element-hq/element-web)) Apache-2.0 Nodejs

Hyphanet

Communication

Anonymously share files, browse and publish _freesites_ (web sites accessible only through Hyphanet) and chat on forums. ([Source Code](https://github.com/hyphanet/fred)) GPL-2.0 Java

Live Helper Chat

Communication

Live Support chat for your website. ([Source Code](https://github.com/LiveHelperChat/livehelperchat)) Apache-2.0 PHP

PushBits

Communication

Notification server for relaying push notifications via Matrix, similar to PushBullet and Gotify. ISC Go

Shhh

Communication

Keep secrets out of emails or chat logs, share them using secure links with passphrase and expiration dates. MIT Python

Synapse

Communication

Server for [Matrix](https://matrix.org/), an open standard for decentralized persistent communication. ([Source Code](https://github.com/element-hq/synapse)) Apache-2.0 Python/deb

RetroShare

Communication

Secured and decentralized communication system. Offers decentralized chat, forums, messaging, file transfer. ([Source Code](https://github.com/RetroShare/RetroShare)) GPL-2.0 C++

Rocket.Chat

Communication

Communications platform that puts data protection first (alternative to Gitter.im and Slack). ([Source Code](https://github.com/RocketChat/Rocket.Chat)) MIT Nodejs/Docker/K8S

Stoat

Communication

Stoat is a user-first chat platform built with modern web technologies. ([Source Code](https://github.com/stoatchat/self-hosted)) AGPL-3.0/MIT Rust

Tox

Communication

Distributed, secure messenger with audio and video chat capabilities. ([Source Code](https://github.com/TokTok/c-toxcore)) GPL-3.0 C

Dovel

Communication

SMTP server that sends and receives emails according to a simple configuration file, with an optional web interface that you can use to browse your emails. ([Source Code](https://dovel.email/server/tr

Mail-in-a-Box

Communication

Turns any Ubuntu server into a fully functional mail server with one command. ([Source Code](https://github.com/mail-in-a-box/mailinabox)) CC0-1.0 Shell

Mailcow

Communication

Mail server suite based on Dovecot, Postfix and other open source software, that provides a modern Web UI for administration. ([Source Code](https://github.com/mailcow/mailcow-dockerized)) GPL-3.0 Doc

Mailu

Communication

Simple yet full-featured mail server as a set of Docker images. ([Source Code](https://github.com/Mailu/Mailu)) MIT Docker/Python

Stalwart Mail Server

Communication

All-in-one mail server with JMAP, IMAP4, and SMTP support and a wide range of modern features. ([Source Code](https://github.com/stalwartlabs/stalwart)) AGPL-3.0 Rust/Docker

Cyrus IMAP

Communication

Email (IMAP/POP3), contacts and calendar server. ([Source Code](https://github.com/cyrusimap/cyrus-imapd)) BSD-3-Clause-Attribution C

Courier MTA

Communication

Fast, scalable, enterprise mail/groupware server providing ESMTP, IMAP, POP3, webmail, mailing list, basic web-based calendaring and scheduling services. ([Source Code](https://www.courier-mta.org/rep

EmailRelay

Communication

A small and easy to configure SMTP and POP3 server for Windows and Linux. ([Source Code](https://sourceforge.net/p/emailrelay/code/HEAD/tree/)) GPL-3.0 C++

OpenSMTPD

Communication

Secure SMTP server implementation from the OpenBSD project. ([Source Code](https://github.com/OpenSMTPD/OpenSMTPD/)) ISC C/deb

Mailman

Communication

Manage electronic mail discussion and e-newsletter lists. ([Source Code](https://gitlab.com/mailman/)) GPL-3.0 Python

Glowing Bear

Communication

A web frontend for WeeChat. ([Demo](https://www.glowing-bear.org)) GPL-3.0 Nodejs

SquirrelMail

Communication

Another browser-based IMAP client. ([Source Code](https://sourceforge.net/p/squirrelmail/code/HEAD/tree/)) GPL-2.0 PHP

Ergo

Communication

Modern IRCv3 server written in Go, combining the features of an ircd, a services framework, and a bouncer. ([Source Code](https://github.com/ergochat/ergo)) MIT Go/Docker

InspIRCd

Communication

Modular IRC server written in C++ for Linux, BSD, Windows, and macOS. ([Source Code](https://github.com/inspircd/inspircd)) GPL-2.0 C++/Docker

Kiwi IRC

Communication

Responsive web IRC client with theming support. ([Demo](https://kiwiirc.com/nextclient/), [Source Code](https://github.com/kiwiirc/kiwiirc)) Apache-2.0 Nodejs

A social network of AI agents generating B2B deals

ntfy

Communication

Push notifications to phone or desktop using HTTP PUT/POST, with Android app, CLI and web app, similar to Pushover and Gotify. ([Demo](https://ntfy.sh/app), [Source Code](https://github.com/binwiederh

SAMA

Communication

Next-Gen self-hosted chat server and clients. ([Demo](https://app.samacloud.io/demo), [Source Code](https://github.com/SAMA-Communications/sama-server), [Clients](https://github.com/SAMA-Communication

Tiledesk

Communication

All-in-one customer engagement platform from lead-gen to post-sales, from WhatsApp to your website. With omni-channel live agents and AI-powered chatbots (alternative to Intercom, Zendesk, Tawk.to and

Maddy Mail Server

Communication

All-in-one mail server that implements SMTP (both MTA and MX) and IMAP. Replaces Postfix, Dovecot, OpenDKIM, OpenSPF, OpenDMARC with single daemon. ([Source Code](https://github.com/foxcpp/maddy)) GPL

Mox

Communication

Complete e-mail solution with IMAP4, SMTP, SPF, DKIM, DMARC, MTA-STS, DANE and DNSSEC, reputation-based and content-based junk filtering, Internationalization (IDNA), automatic TLS with ACME and Let's

Roundcube

Communication

Browser-based IMAP client with an application-like user interface. ([Source Code](https://github.com/roundcube/roundcubemail)) GPL-3.0 PHP/deb

SIP3

Communication

VoIP troubleshooting and monitoring platform. ([Demo](https://demo.sip3.io), [Source Code](https://github.com/sip3io/)) Apache-2.0 Java

SIPCAPTURE Homer

Communication

Troubleshooting and monitoring VoIP calls. ([Source Code](https://github.com/sipcapture/homer)) AGPL-3.0 Nodejs/Go/Docker

Misskey

Communication

Decentralized app-like microblogging server/SNS for the Fediverse, using the ActivityPub protocol like GNU social and Mastodon. ([Source Code](https://github.com/misskey-dev/misskey)) AGPL-3.0 Nodejs/

OSSN

Communication

Social networking software that allows you to make a social networking website and helps your members build social relationships, with people who share similar professional or personal interests. ([So

ejabberd

Communication

XMPP instant messaging server. ([Source Code](https://github.com/processone/ejabberd)) GPL-2.0 Erlang/Docker

OpenRouteService

Communication

Route service with directions, isochrones, time-distance matrix, route optimization, etc. ([Demo](https://openrouteservice.org/dev/#/api-docs/introduction), [Source Code](https://github.com/GIScience/

Owncast

Communication

Decentralized single-user live video streaming and chat server for running your own live streams similar in style to the large mainstream options. ([Source Code](https://github.com/owncast/owncast)) M

ReadAny

Communication

AI-powered e-book reader with semantic search, chat, and note management. [![Open-Source Software][OSS Icon]](https://github.com/codedogQBY/ReadAny) ![Freeware][Freeware Icon]

PDF Pals

Communication

Chat with PDF app for Mac. No file size limits!

pgMagic🪄

Communication

Chat to Postgres in natural language or SQL.

Jan

Communication

An open-source alternative to ChatGPT that runs entirely offline on your computer. [![Open-Source Software][OSS Icon] ![Freeware][Freeware Icon]](https://github.com/menloresearch/jan)

Ferdium

Communication

Messaging workspace that combines multiple web apps in one place. [![Open-Source Software][OSS Icon] ![Freeware][Freeware Icon]](https://github.com/ferdium/ferdium-app)

Keybase

Communication

Secure groups, files, and chat for everyone! [![Open-Source Software][OSS Icon]](https://github.com/keybase) ![Freeware][Freeware Icon]

Mastodon

Communication

Your self-hosted, globally interconnected microblogging community [![Freeware][Freeware Icon]](https://joinmastodon.org/apps) [![Open-Source Software][OSS Icon]](https://github.com/mastodon/mastodon)

Telegram

Communication

Messaging app with a focus on speed and security. [![Open-Source Software][OSS Icon]](https://github.com/overtake/TelegramSwift) [![App Store][app-store Icon]](https://apps.apple.com/us/app/telegram/i

Audio Hijack

Communication

Record any application's audio, including VoIP calls from Skype, web streams from Safari, and much more.

Chatbox

Communication

User-friendly Desktop Client App for AI Models/LLMs (GPT, Claude, Gemini, Ollama...). [![Open-Source Software][OSS Icon] ![Freeware][Freeware Icon]](https://github.com/chatboxai/chatbox)

Macaify

Communication

Fast use of ChatGPT, lightweight, clean, keyboard-first. ![Freeware][Freeware Icon]

Mattermost

Communication

a flexible, open-source messaging platform that meets even the most demanding privacy and security standards. ![open-source.svg](https://github.com/LisaDziuba/Awesome-Design-Tools/blob/master/Media/op

Tigase

Communication

XMPP server implementation in Java.

Kaiwa

Communication

Web based chat client in the style of common paid alternatives.

Kafka

Communication

A high-throughput distributed messaging system.

Claws Mail

Communication

Old school email client (and news reader), based on GTK+. ([Source Code](https://git.claws-mail.org/?p=claws.git;a=tree)) GPL-3.0 C

OpenTrashmail

Communication

Complete trashmail solution that exposes an SMTP server and has a web interface to manage received emails. Works with multiple and wildcard domains and is fully file based (no database needed). Includ

clevercli

Communication

Collection of ChatGPT powered utilities.

Errbot

Communication

Plugin based chatbot designed to be easily deployable, extensible and maintainable. ([Source Code](https://github.com/errbotio/errbot)) GPL-3.0 Python

RecurseChat

Communication

Local-first AI chat app with customizable workflows.

Jitsi

Communication

multi-platform open-source video conferencing you can install yourself or use on their servers.  ![open-source

ImapSync

Communication

Simple IMAP migration tool for copying mailboxes to other servers. ([Source Code](https://github.com/imapsync/imapsync)) NLPL Perl

Mutt

Communication

Small but very powerful text-based mail client. ([Source Code](https://gitlab.com/muttmua/mutt)) GPL-2.0 C

Sylpheed

Communication

Still developed predecessor to Claws Mail, lightweight mail client. ([Source Code](https://github.com/sylpheed-mail/sylpheed)) GPL-2.0 C

Tau

Communication

Easily build Cloud Computing Platforms with features like Serverless WebAssembly Functions, Frontend Hosting, CI/CD, Object Storage, K/V Database, and Pub-Sub Messaging. ([Source Code](https://github.

ArsTechnica OpenForum

Communication

IT Forum which is attached to a large news site.

Pleroma

Communication

Federated microblogging server, Mastodon, GNU social, & ActivityPub compatible. ([Source Code](https://git.pleroma.social/pleroma/pleroma)) AGPL-3.0 Elixir

MailCatcher

Communication

Ruby gem that deploys a simply SMTP MTA gateway that accepts all mail and displays in web interface. Useful for debugging or development.

docker-mailserver

Communication

Production-ready fullstack but simple mail server (SMTP, IMAP, LDAP, Antispam, Antivirus, etc.) running inside a container. Only configuration files, no SQL database. ([Source Code](https://github.com

AWStats

Communication

Generate statistics from web, streaming, ftp or mail server logfiles. ([Demo](https://www.awstats.org/#DEMO), [Source Code](https://github.com/eldy/awstats)) GPL-3.0 Perl

Mumble

Communication

Low-latency, high quality voice/text chat software. ([Source Code](https://github.com/mumble-voip/mumble), [Clients](https://wiki.mumble.info/wiki/3rd_Party_Applications)) BSD-3-Clause C++/deb

Tuwunel

Communication

High-performance and feature-rich chat server for Matrix, and the successor to conduwuit (fork of Conduit). ([Demo](https://try.tuwunel.chat/), [Source Code](https://github.com/matrix-construct/tuwune

The Lounge

Communication

Self-hosted web IRC client. ([Demo](https://demo.thelounge.chat/), [Source Code](https://github.com/thelounge/thelounge)) MIT Nodejs/Docker

Noosfero

Communication

Platform for social and solidarity economy networks with blog, e-Portfolios, CMS, RSS, thematic discussion, events agenda and collective intelligence for solidarity economy in the same system. AGPL-3.

Jitsi Video Bridge

Communication

WebRTC compatible Selective Forwarding Unit (SFU) that allows for multiuser video communication. ([Source Code](https://github.com/jitsi/jitsi-videobridge)) Apache-2.0 Java/deb

Citadel

Communication

Groupware including email, calendar/scheduling, address books, forums, mailing lists, IM, wiki and blog engines, RSS aggregation and more. ([Source Code](https://www.citadel.org/source.html)) GPL-3.0

remio

Communication

Local-first AI chat client that answers from your knowledge base. [![Freeware][Freeware Icon]](https://www.remio.ai/?utm_source=github_list)

chasquid

Communication

SMTP (email) server with a focus on simplicity, security, and ease of operation. ([Source Code](https://blitiri.com.ar/git/r/chasquid/)) Apache-2.0 Go

strip-css-comments-cli

Communication

Strip comments from CSS.

Continuwuity

Communication

Community-driven Matrix homeserver, the continuation of conduwuit focusing on user experience and new features (fork of Conduit). ([Source Code](https://forgejo.ellis.link/continuwuation/continuwuity)

Dittofeed

Communication

Omni-channel customer engagement and messaging automation platform (alternative to Braze, Customer.io, Iterable). ([Demo](https://demo.dittofeed.com/dashboard/journeys), [Source Code](https://github.c

strip-json-comments-cli

Communication

Strip comments from JSON.

Teams

Communication

Free online meetings and video calls

Databag

Communication

Federated, end-to-end encrypted messaging service for the web, iOS, and Android, supporting text, photos, video, and WebRTC video and audio calls. ([Demo](https://databag.coredb.org/#/create)) Apache-

SnappyMail

Communication

Simple, modern, lightweight & fast web-based email client (fork of RainLoop). ([Demo](https://snappymail.eu/demo/), [Source Code](https://github.com/the-djmaze/snappymail), [Clients](https://snappymai

GoToSocial

Communication

ActivityPub federated social network server implementing the Mastodon client API. ([Source Code](https://codeberg.org/superseriousbusiness/gotosocial)) AGPL-3.0 Docker/Go

Hatsu

Communication

Bridge that interacts with Fediverse on behalf of your static site. ([Source Code](https://github.com/importantimport/hatsu)) AGPL-3.0 Docker/Rust

MiroTalk SFU

Communication

Simple, secure, scalable real-time video conferences up to 4k, compatible with all browsers and platforms. ([Demo](https://sfu.mirotalk.com/newroom), [Source Code](https://github.com/miroslavpejic85/m

Gotify

Communication

Notification server with Android and CLI clients (alternative to PushBullet). ([Source Code](https://github.com/gotify/server), [Clients](https://github.com/gotify/android)) MIT Go/Docker

Discourse

Communication

Advanced forum / community solution based on Ruby and JS. ([Demo](https://try.discourse.org/), [Source Code](https://github.com/discourse/discourse)) GPL-2.0 Docker

Postal

Communication

Complete and fully featured mail server for use by websites & web servers. ([Source Code](https://github.com/postalserver/postal)) MIT Docker/Ruby

Langfuse

Communication

LLM engineering platform for model tracing, prompt management, and application evaluation. Langfuse helps teams collaboratively debug, analyze, and iterate on their LLM applications such as chatbots o

Castopod

Communication

Podcast management hosting platform that includes the latest podcast 2.0 standards, an automated Fediverse feed, analytics, an embeddable player, and more. ([Source Code](https://code.castopod.org/ada

Rambox

Communication

Messaging and emailing app that combines common web applications into one. [![Open-Source Software][OSS Icon]](https://github.com/saenzramiro/rambox) ![Freeware][Freeware Icon]

Misskey

Communication

🌎 A completely free and open interplanetary microblogging platform 🚀 [![Open-Source Software][OSS Icon]](https://github.com/misskey-dev/misskey)

HomeServerHQ

Communication

All-in-one home server infrastructure and installer. Have a fully configured email server, VPN, and public website(s) set up in less than an hour, even behind CGNAT. ([Source Code](https://github.com/

Pomodoro, to do list & habit tracker with Eisenhower Matrix

Poe

Communication

Multi-model AI chat platform

Robust IRC

Communication

IRC without netsplits. Distributed IRC server, based on RobustSession protocol. ([Source Code](https://github.com/robustirc/robustirc)) BSD-3-Clause Go

Weechat

Communication

Fast, light and extensible chat client. ([Source Code](https://github.com/weechat/weechat)) GPL-3.0 C/Docker/deb

Asterisk

Communication

Easy to use but advanced IP PBX system, VoIP gateway and conference server. ([Source Code](https://github.com/asterisk/asterisk)) GPL-2.0 C/deb

Akkoma

Communication

Federated microblogging server with Mastodon, GNU social, and ActivityPub compatibility. ([Source Code](https://akkoma.dev/AkkomaGang/akkoma)) AGPL-3.0 Elixir/Docker

diaspora*

Communication

Distributed social networking server. ([Source Code](https://github.com/diaspora/diaspora)) AGPL-3.0 Ruby

HumHub

Communication

Flexible kit for private social networks. ([Source Code](https://github.com/humhub/humhub)) AGPL-3.0 PHP

Iceshrimp.NET

Communication

Federated microblogging server that communicates over ActivityPub. ([Source Code](https://iceshrimp.dev/iceshrimp/iceshrimp.net)) EUPL-1.2 .NET/C#/Docker

Isso

Communication

Lightweight commenting server written in Python and Javascript. It aims to be a drop-in replacement for Disqus. ([Source Code](https://github.com/isso-comments/isso)) MIT Python/Docker

Lemmy

Communication

Link aggregator for the fediverse (alternative to Reddit). ([Source Code](https://github.com/LemmyNet/lemmy)) AGPL-3.0 Docker/Rust

Misago

Communication

Fully featured modern forum application that is fast, scalable and responsive. ([Source Code](https://github.com/rafalp/Misago)) GPL-2.0 Docker

Movim

Communication

Modern, federated social network based on XMPP, with a fully featured group-chat, subscriptions and microblogging. ([Source Code](https://github.com/movim/movim)) AGPL-3.0 PHP/Docker

NodeBB

Communication

Forum software built for the modern web. ([Demo](https://try.nodebb.org/), [Source Code](https://github.com/NodeBB/NodeBB)) GPL-3.0 Nodejs/Docker

phpBB

Communication

Flat-forum bulletin board software solution that can be used to stay in touch with a group of people or can power your entire website. ([Source Code](https://github.com/phpbb/phpbb)) GPL-2.0 PHP

remark42

Communication

Lightweight and simple comment engine, which doesn't spy on users. It can be embedded into blogs, articles or any other place where readers add comments. ([Demo](https://remark42.com/demo/), [Source C

BigBlueButton

Communication

Supports real-time sharing of audio, video, slides (with whiteboard controls), chat, and the screen. Instructors can engage remote students with polling, emojis, and breakout rooms. ([Source Code](htt

Galene

Communication

Video conferencing server that is easy to deploy and that requires moderate server resources. ([Source Code](https://github.com/jech/galene)) MIT Go

Jitsi Meet

Communication

WebRTC application that uses Jitsi Videobridge to provide high quality, scalable video conferences. ([Demo](https://meet.jit.si), [Source Code](https://github.com/jitsi/jitsi-meet)) Apache-2.0 Nodejs/

MiroTalk C2C

Communication

Real-time cam-2-cam video calls & screen sharing, end-to-end encrypted, to embed in any website with a simple iframe. ([Source Code](https://github.com/miroslavpejic85/mirotalkc2c)) AGPL-3.0 Nodejs/Do

MiroTalk P2P

Communication

Simple, secure, fast real-time video conferences up to 4k and 60fps, compatible with all browsers and platforms. ([Demo](https://p2p.mirotalk.com/newcall), [Source Code](https://github.com/miroslavpej

MongooseIM

Communication

Mobile messaging platform with a focus on performance and scalability. ([Source Code](https://github.com/esl/MongooseIM)) GPL-2.0 Erlang/Docker/K8S

Tigase

Communication

XMPP server implementation in Java. ([Source Code](https://github.com/tigase/tigase-server)) GPL-3.0 Java

Converse.js

Communication

XMPP chat client in your browser. ([Source Code](https://github.com/conversejs/converse.js)) MPL-2.0 Javascript

Peergos

Communication

Secure and private space online where you can store, share and view your photos, videos, music and documents. Also includes a calendar, news feed, task lists, chat and email client. ([Source Code](htt

Colanode

Communication

Collaboration suite with real-time messaging, rich text pages, file management, and dynamic databases - built for offline work (alternative to Slack, Notion). ([Source Code](https://github.com/colanod

Openmeetings

Communication

Video conferencing, instant messaging, whiteboard, collaborative document editing and other groupware tools using API functions of the Red5 Streaming Server for Remoting and Streaming. ([Source Code](

SOGo

Communication

SOGo offers multiple ways to access the calendaring and messaging data. CalDAV, CardDAV, GroupDAV, as well as ActiveSync, including native Outlook compatibility and Web interface. ([Demo](https://demo

PrivateBin

Communication

Minimalist pastebin/discussion board where the server has zero knowledge of hosted data. ([Demo](https://privatebin.net/), [Source Code](https://github.com/PrivateBin/PrivateBin)) Zlib PHP

Mobilizon

Communication

Federated tool that helps you find, create and organise events and groups. ([Source Code](https://framagit.org/framasoft/mobilizon/)) AGPL-3.0 Elixir/Docker

Syncloud

Communication

Your own online file storage, social network or email server. ([Source Code](https://github.com/syncloud/platform)) GPL-3.0 Go/Shell

Pagure

Communication

Lightweight, powerful, and flexible git-centric forge with features laying the foundation for federated and decentralized development. ([Demo](https://pagure.io/)) GPL-2.0 Docker/Python/deb

Gitter

Communication

Chat platform for developers and GitHub communities. ![Freeware][Freeware Icon]

Franz

Communication

Messaging app that combines multiple chat services in one place. ![Freeware][Freeware Icon]

Lark

Communication

The Next-Gen Collaboration Suite. All your chats, meetings, calendars, docs, and emails in one place. ![Freeware][Freeware Icon]

LimeChat

Communication

Open-source IRC client for Mac OS X. [![Open-Source Software][OSS Icon] ![Freeware][Freeware Icon]](https://github.com/psychs/limechat)

Mattermost

Communication

Open-source team collaboration platform. [![Open-Source Software][OSS Icon]](https://github.com/mattermost/mattermost) ![Freeware][Freeware Icon]

Postbox

Communication

Powerful, simple and beautiful email client, need to pay for a license.

WeChat

Communication

Official WeChat app for Mac. ![Freeware][Freeware Icon] ![App Store][app-store Icon]

Foxmail

Communication

Fast email client. ![Freeware][Freeware Icon]

Mailspring

Communication

A beautiful, fast, and fully open source mail client. [![Open-Source Software][OSS Icon]](https://github.com/Foundry376/Mailspring) ![Freeware][Freeware Icon]

MindMac

Communication

AI chat client for multiple providers in one place.

Selectric

Communication

Private search across email, documents, and chat apps.

Lens Studio

Communication

create, publish, and share your own AR experiences for Snapchat with or without code. 

Flexisip

Communication

Complete, modular and scalable SIP server, includes a push gateway, to deliver SIP incoming calls or text messages on mobile device platforms where push notifications are required to receive informati

cpp-linter-action

Communication

A Github Action for linting C/C++ code integrating clang-tidy and clang-format to collect feedback provided in the form of thread comments and/or annotations.

Eggdrop

Communication

The world's most popular Open Source IRC bot, designed for flexibility and ease of use.

Err

Communication

A plugin based chatbot designed to be easily deployable, extensible and maintainable.

Lita

Communication

A robot companion for your company's chat room.

Maildrop

Communication

Open Source disposable email SMTP server, also useful for development.

Courier IMAP/POP3

Communication

Fast, scalable, enterprise IMAP and POP3 server.

NSQ

Communication

A realtime distributed messaging platform.

ZeroMQ

Communication

High-performance asynchronous messaging library.

DevOpsLinks

Communication

A community of DevOps, SysAdmin & Developers with a weekly newsletter and a team chat.

ngircd

Communication

Portable and lightweight Internet Relay Chat server for small or private networks. ([Source Code](https://github.com/ngircd/ngircd)) GPL-2.0 C/deb

BoltAI

Communication

A beautiful & powerful ChatGPT app for Mac. Stay ahead by integrating AI into your workflow today.

UnrealIRCd

Communication

Modular, advanced and highly configurable IRC server written in C for Linux, BSD, Windows, and macOS. ([Source Code](https://github.com/unrealircd/unrealircd)) GPL-2.0 C

Corteza

Communication

CRM including a unified workspace, enterprise messaging and a low code environment for rapidly and securely delivering records-based management solutions. ([Demo](https://latest.cortezaproject.org), [

ZNC

Communication

Advanced IRC bouncer. ([Source Code](https://github.com/znc/znc)) Apache-2.0 C++/deb

Polymail

Communication

Simple, beautiful and powerful email client. ![Freeware][Freeware Icon]

Zulip

Communication

Zulip is a powerful, open source group chat application. ([Source Code](https://github.com/zulip/zulip)) Apache-2.0 Python

Artalk

Communication

Comment system built in Golang, providing a lightweight and highly customizable solution for adding comments to your website. ([Source Code](https://github.com/ArtalkJS/Artalk)) MIT Go/Docker

wildduck

Communication

Scalable no-SPOF IMAP/POP3 mail server. ([Source Code](https://github.com/zone-eu/wildduck)) EUPL-1.2 Nodejs/Docker

Teambition

Communication

Team collaboration tool for tasks, schedules, files, and discussions. ![Freeware][Freeware Icon]

Adium

Communication

Free instant messaging application for Mac OS X. Connect to AIM, MSN, SMPP, Yahoo and more. ![Freeware][Freeware Icon]

DingTalk

Communication

Team communication and collaboration platform. ![Freeware][Freeware Icon]

Haraka

Communication

Fast, highly extensible, and event driven SMTP server. ([Source Code](https://github.com/haraka/Haraka)) MIT Nodejs

Airmail

Communication

Fast email client. For both Mac OS and iOS.

Mastodon

Communication

Federated microblogging server. ([Source Code](https://github.com/mastodon/mastodon), [Clients](https://github.com/hyperupcall/awesome-mastodon)) AGPL-3.0 Ruby

Flarum

Communication

Delightfully simple forums. Flarum is the next-generation forum software that makes online discussion fun again. ([Source Code](https://github.com/flarum/flarum)) MIT PHP

Zimbra

Communication

Collaborative software suite, that includes an email server and web client.

MyBB

Communication

Free, extensible forum software package. ([Source Code](https://github.com/mybb/mybb)) LGPL-3.0 PHP

WriteFreely

Communication

Writing software for starting a minimalist, federated blog — or an entire community. ([Source Code](https://github.com/writefreely/writefreely)) AGPL-3.0 Go

Edison Mail

Communication

A customisable, simple, and beautiful email client. ![Freeware][Freeware Icon]

CloudBot

Communication

The simple, fast, expandable, open-source Python IRC bot.

Centrifugo

Communication

Language-agnostic real-time messaging (Websocket or SockJS) server. ([Demo](https://github.com/centrifugal/centrifugo#demo), [Source Code](https://github.com/centrifugal/centrifugo)) MIT Go/Docker/K8S

Smarter, more personal answers as ChatGPT's new default

ChatGPT Atlas

Communication

Browser with ChatGPT built in. ![Freeware][Freeware Icon]

Tabbit

Communication

An AI-native browser that understands your context, chats with webpages, and automates tasks. ![Freeware][Freeware Icon]

Spectrum 2

Communication

Spectrum 2 is an open source instant messaging transport. It allows users to chat together even when they are using different IM networks. ([Source Code](https://github.com/SpectrumIM/spectrum2)) GPL

CyTube

Communication

Synchronize media, chat, and more for an arbitrary number of channels. ([Demo](https://cytu.be)) MIT Nodejs

Prosody IM

Communication

Feature-rich and easy to configure XMPP server. ([Source Code](https://hg.prosody.im/)) MIT Lua

Snikket

Communication

All-in-one Dockerized easy XMPP solution, including web admin and clients. ([Source Code](https://github.com/snikket-im/snikket-server), [Clients](https://snikket.org/app/)) Apache-2.0 Docker

Chitchatter

Communication

Peer-to-peer chat app that is serverless, decentralized, and ephemeral. ([Source Code](https://github.com/jeremyckahn/chitchatter)) GPL-2.0 Nodejs

NeoMutt

Communication

Email client.

aye-chat

Communication

Workspace for editing, running commands, and chatting with your codebase.

Zulip

Communication

combines the immediacy of real-time chat with an email threading model, helping to focus on important conversations while ignoring irrelevant ones. ![open-source.svg](https://github.com/LisaDziuba/Awe

Elgg

Communication

Powerful open source social networking engine. ([Source Code](https://github.com/Elgg/Elgg)) GPL-2.0 PHP

Socialhome

Communication

Federated and decentralized profile builder and social network engine. ([Demo](https://socialhome.network/), [Source Code](https://github.com/jaywink/socialhome)) AGPL-3.0 Docker/Python

Self-hosted email marketing. BYO SMTP, zero cost per email.

AI chat and API that keeps your conversations fully private

Onyx Community Edition

Communication

Chat UI that works with any LLM. It comes loaded with advanced features like agents, web search, RAG, MCP, deep research, Connectors to 40+ knowledge sources, and more. ([Source Code](https://github.c

Lazlo

Communication

A chatops automation framework in Go.

PushMate

Communication

Solves common push notification problems on macOS.