In a world that's continually advancing technologically, the importance and usefulness of free and open-source software (FOSS) cannot be overstated. Not only does FOSS contribute to increased learning and innovation, but it also encourages collaboration, fostering a sense of community among developers and users alike. This directory, as well as the resources provided at the end, offer a comprehensive overview of the available alternatives for businesses.

This is a work in progress. Please contribute!

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These platforms, providing alternatives to widely-used services like Slack and Discord, offer features ranging from real-time messaging and file sharing, to video conferencing and task management.

• Element ★10090 - A glossy Matrix collaboration client for the web. [TS, Apache License 2.0].
• Mattermost ★26285 - Mattermost is an open source platform for secure collaboration across the entire software development lifecycle.. [TS, Other license].
• RelatedChat ★4596 - Open source alternative communication platform. [Swift, MIT License].
• Rocket.chat ★37028 - The communications platform that puts data protection first. [TS, Other license].
• Spacebar ★5008 - 📬 Spacebar is a free open source selfhostable discord compatible communication platform. [GNU Affero General Public License v3.0].
• Zulip ★18444 - Zulip server and web application. Open-source team chat that helps teams stay productive and focused. [🐍, Apache License 2.0].

The modern workplace often spans cities, countries, and even continents, making effective virtual communication tools essential. These alternatives to popular services such as Zoom, Webex, Google Meet, Skype, etc., offer features like video and audio calls, screen sharing, virtual meetings, and webinars.

• BigBlueButton ★8082 - Complete open source web conferencing system. [JS, GNU Lesser General Public License v3.0].
• Element Call ★377 - Group calls powered by Matrix. [TS, Apache License 2.0].
• Galene ★785 - The Galène videoconference server. [Go, MIT License].
• Jitsi Meet ★20318 - Jitsi Meet - Secure, Simple and Scalable Video Conferences that you use as a standalone app or embed in your web application. [TS, Apache License 2.0].

Knowledge is the cornerstone of any successful organization, and managing it effectively is crucial. This category focuses on platforms that provide a means for businesses and individuals to store, organize, and share information effectively. These alternatives to Notion - a popular collaboration platform - offer users a versatile and interactive environment for creating, managing, and sharing digital content. From taking notes, tracking tasks, managing projects to creating an internal wiki, these FOSS options provide an array of features that support diverse knowledge management needs while aligning with the principles of openness, flexibility, and community-oriented development.

• AFFiNE ★22276 - There can be more than Notion and Miro. AFFiNE is a next-gen knowledge base that brings planning, sorting and creating all together. Privacy first, open-source, customizable and ready to use. [TS, Other license].
• AppFlowy ★38604 - AppFlowy is an open-source alternative to Notion. You are in charge of your data and customizations. Built with Flutter and Rust. [Dart, GNU Affero General Public License v3.0].
• BookStack ★12219 - A platform to create documentation/wiki content built with PHP & Laravel. [PHP, MIT License].
• MoinMoin ★259 - MoinMoin Wiki Development (2.0+), unstable, for production please use 1.9.x. [🐍, Other license].
• XWiki ★864 - The XWiki platform. [☕️, GNU Lesser General Public License v2.1].
• MediaWiki ★3609 - 🌻 The collaborative editing software that runs Wikipedia. Mirror from https://gerrit.wikimedia.org/g/mediawiki/core. See https://mediawiki.org/wiki/Developer_access for contributing. [PHP, Other license].

More:

• WikiMatrix - Compare them all. (WikiMatrix helps you compare the features of many different Wikis in a comfortable side-by-side table.).
• List of wiki software on Wikipedia.
• List of Wiki Engines ow C2. (Exhaustive list of wiki engines, including long-dead ones, with a short description of each one).

These tools are designed to help individuals maintain control over their personal knowledge sphere. These platforms, offering an alternative to the popular Evernote service, enable users to record thoughts, capture information from various sources, and organize these snippets of knowledge in a way that best suits their unique cognitive and workflow preferences.

• Joplin ★38630 - Joplin - the secure note taking and to-do app with synchronisation capabilities for Windows, macOS, Linux, Android and iOS. [TS, Other license].
• Logseq ★24975 - A privacy-first, open-source platform for knowledge management and collaboration. Download link: https://github.com/logseq/logseq/releases. roadmap: https://trello.com/b/8txSM12G/roadmap. [Clojure, GNU Affero General Public License v3.0].
• Notesnook ★6964 - A fully open source & end-to-end encrypted note taking alternative to Evernote. [TS, GNU General Public License v3.0].
• SiYuan ★12207 - A privacy-first, self-hosted, fully open source personal knowledge management software, written in typescript and golang. [TS, GNU Affero General Public License v3.0].

The way we organize and manage our tasks has a significant impact on productivity, and so called "Kanban boards" have proven to be a powerful tool in this regard, by facilitating the visual management of work using the Kanban methodology. These alternatives to Trello offer features such as task cards, customizable boards, and progress tracking that help individuals and teams visualize workflow, manage work-in-progress, and enhance overall productivity.

• Focalboard ★15978 - Focalboard is an open source, self-hosted alternative to Trello, Notion, and Asana. [TS, Other license].
• Kanboard ★7732 - Kanban project management software. [PHP, MIT License].
• Planka ★3145 - The realtime kanban board for workgroups built with React and Redux. [JS, GNU Affero General Public License v3.0].
• WeKan ★18765 - The Open Source kanban (built with Meteor). Keep variable/table/field names camelCase. For translations, only add Pull Request changes to wekan/i18n/en.i18n.json , other translations are done at https://app.transifex.com/wekan/ only. [JS, MIT License].

• Crater ★7249 - Open Source Invoicing Solution for Individuals & Businesses. [PHP, GNU Affero General Public License v3.0].
• Invoice Ninja ★7301 - Invoices, Expenses and Tasks built with Laravel, Flutter and React. [PHP, Other license].
• SolidInvoice ★480 - Simple and elegant invoicing solution. [PHP, MIT License].

• Dolibarr ★4200 - ERP, CRM, POS, RH
• ERP5 ★169 - ERP5 Open Source ERP/CRM/KM. (Mirror of https://lab.nexedi.com/nexedi/erp5 ; Please submit patches and issues there). [JS, Unknown license].
• Odoo ★30661 - Odoo. Open Source Apps To Grow Your Business. [JS, Other license].

• SuiteCRM ★3732 - SuiteCRM - Open source CRM for the world. [PHP, GNU Affero General Public License v3.0].
• EspoCRM ★1230 - EspoCRM – Open Source CRM Application. [PHP, GNU General Public License v3.0].

• Alfresco ★170 - Alfresco Content Application. [TS, GNU Lesser General Public License v3.0].
• Nuxeo ★571 - Content management platform to build modern business applications. [☕️, Unknown license].
• OpenKM ★608 - OpenKM is a Open Source Document Management System. [☕️, GNU General Public License v2.0].
• LogicalDOC ★76 - LogicalDOC Community open source document management system https://www.logicaldoc.com. [☕️, GNU Lesser General Public License v3.0].
• Mayan EDMS - Free Open Source DMS (document management system).

• Wordpress ★17968 - WordPress, Git-ified. This repository is just a mirror of the WordPress subversion repository. Please do not send pull requests. Submit pull requests to https://github.com/WordPress/wordpress-develop and patches to https://core.trac.wordpress.org/ instead. [PHP, Other license].
• Ghost ★43986 - Turn your audience into a business. Publishing, memberships, subscriptions and newsletters. [JS, MIT License].

More:

• List of content management systems on Wikipedia (not all open source)

• btw ★291 - Open source Medium alternative- set up your personal blog in minutes. [JS, GNU General Public License v3.0].
• WriteFreely ★3796 - A clean, Markdown-based publishing platform made for writers. Write together and build a community. [Go, GNU Affero General Public License v3.0].

• Matomo ★18165 - Liberating Web Analytics. Star us on Github? +1. Matomo is the leading open alternative to Google Analytics that gives you full control over your data. Matomo lets you easily collect data from websites & apps and visualise this data and extract insights. Privacy is built-in. We love Pull Requests!. [PHP, GNU General Public License v3.0].
• Plausible ★16063 - Simple, open-source, lightweight (< 1 KB) and privacy-friendly web analytics alternative to Google Analytics. [💧, GNU Affero General Public License v3.0].
• Shynet ★2549 - Modern, privacy-friendly, and detailed web analytics that works without cookies or JS. [🐍, Apache License 2.0].
• Umami ★16977 - Umami is a simple, fast, privacy-focused alternative to Google Analytics. [JS, MIT License].

• 11ty ★15038 - A simpler site generator. Transforms a directory of templates (of varying types) into HTML. [JS, MIT License].
• Hugo ★69036 - The world’s fastest framework for building websites. [Go, Apache License 2.0].
• Jekyll ★47249 - 🌐 Jekyll is a blog-aware static site generator in Ruby. [💎, MIT License].
• Lektor ★3695 - The lektor static file content management system. [🐍, BSD 3-Clause "New" or "Revised" License].
• Zola ★11569 - A fast static site generator in a single binary with everything built-in. https://www.getzola.org. [🦀, MIT License].

More:

• A List of Static Site Generators for Jamstack Sites
• Awesome Static Web Site Generators ★2339 - A curated list of static web site generators. [Creative Commons Zero v1.0 Universal].

• Abilian Nua ★29 - Open source PaaS and application marketplace. [🐍, GNU Affero General Public License v3.0].
• CapRover ★10961 - Scalable PaaS (automated Docker+nginx) - aka Heroku on Steroids. [TS, Other license].
• Coolify ★8907 - An open-source & self-hostable Heroku / Netlify alternative. Cloud version available here -> https://app.coolify.io. [PHP, Apache License 2.0].
• Dokku ★24965 - A docker-powered PaaS that helps you build and manage the lifecycle of applications. [Shell, MIT License].

• Janssen ★275 - Welcome to the Janssen Project, a collaboration hub for digital identity infrastructure software... and introducing Agama--a programming language and archive format for interoperable identity orchestration!. [☕️, Apache License 2.0].
• Keycloak ★17410 - Open Source Identity and Access Management For Modern Applications and Services. [☕️, Apache License 2.0].
• Logto ★6297 - 🧑‍🚀 Logto is a modern Auth0 alternative for building identity infrastructure with minimal effort, for both your customers and their organizations. [TS, Mozilla Public License 2.0].
• SuperTokens ★10049 - Open source alternative to Auth0 / Firebase Auth / AWS Cognito. [☕️, Other license].

• Mellisearch ★38840 - A lightning-fast search engine that fits effortlessly into your apps, websites, and workflow. [🦀, MIT License].
• Sonic ★18575 - 🦔 Fast, lightweight & schema-less search backend. An alternative to Elasticsearch that runs on a few MBs of RAM. [🦀, Mozilla Public License 2.0].
• Tantivy ★8717 - Tantivy is a full-text search engine library inspired by Apache Lucene and written in Rust. [🦀, MIT License].
• Typesense ★14839 - Open Source alternative to Algolia + Pinecone and an Easier-to-Use alternative to ElasticSearch ⚡ 🔍 ✨ Fast, typo tolerant, in-memory fuzzy Search Engine for building delightful search experiences. [C++, GNU General Public License v3.0].

• Appwrite ★33146 - Build Fast. Scale Big. All in One Place. Cloud is now available in public beta. 🌩. [TS, BSD 3-Clause "New" or "Revised" License].
• Nhost ★6971 - The Open Source Firebase Alternative with GraphQL. [TS, MIT License].
• Supabase ★56828 - The open source Firebase alternative. Follow to stay updated about our public Beta. [TS, Apache License 2.0].

• Apprise ★8625 - Apprise - Push Notifications that work with just about every platform!. [🐍, BSD 3-Clause "New" or "Revised" License].
• Novu ★24406 - The open-source notification infrastructure with fully functional embedded notification center. [TS, MIT License].
• ntfy ★13708 - Send push notifications to your phone or desktop using PUT/POST. [Go, Apache License 2.0].

• Hook0 ★236 - Open-Source webhooks api and server that makes it easy for developers to send webhooks from their app and SaaS. [☕️, Other license].

• Graylog ★6744 - Free and open log management. [☕️, Other license].

• hyperdx ★1371 - Resolve production issues, fast. An open source observability platform unifying session replays, logs, metrics, traces and errors. [TS, MIT License].
• signoz ★14314 - SigNoz is an open-source APM. It helps developers monitor their applications & troubleshoot problems, an open-source alternative to DataDog, NewRelic, etc. 🔥 🖥. 👉 Open source Application Performance Monitoring (APM) & Observability tool. [TS, Other license].
• Sentry ★35129 - Developer-first error tracking and performance monitoring. [🐍, Other license].

• Bugzilla ★578 - Official repository for the Bugzilla bug tracking system. Report bugs to https://bugzilla.mozilla.org/enter_bug.cgi?product=Bugzilla&format=__default__ . Main website:. [Perl, Mozilla Public License 2.0].
• Plane ★15015 - 🔥 🔥 🔥 Open Source JIRA, Linear and Height Alternative. Plane helps you track your issues, epics, and product roadmaps in the simplest way possible. [TS, GNU Affero General Public License v3.0].
• Redmine ★4889 - Mirror of redmine code source - Official Subversion repository is at https://svn.redmine.org/redmine - contact: @vividtone or maeda (at) farend (dot) jp. [💎, Unknown license].
• Taiga ★5809 - Agile project management platform. Built on top of Django and AngularJS. [🐍, GNU Affero General Public License v3.0].

• Gitea ★38352 - Git with a cup of tea! Painless self-hosted all-in-one software development service, including Git hosting, code review, team collaboration, package registry and CI/CD. [Go, MIT License].
• Gitlab ★23364 - GitLab CE Mirror | Please open new issues in our issue tracker on GitLab.com. [💎, Other license].
• Gogs ★42919 - Gogs is a painless self-hosted Git service. [Go, MIT License].
• Pagure ★195 - pagure is a light-weight git-centered forge based on pygit2. (MIRROR). [🐍, GNU General Public License v2.0].
• Sourcehut - This suite of open source tools is the software development platform you've been waiting for.

• Buildbot ★5076 - Python-based continuous integration testing framework; your pull requests are more than welcome!. [🐍, GNU General Public License v2.0].
• Drone ★27272 - Drone is a Container-Native, Continuous Delivery Platform. [Go, Other license].
• Jenkins ★21435 - Jenkins automation server. [☕️, MIT License].

• Gerrit ★817 - Gerrit Code Review - (mirror of https://gerrit.googlesource.com/gerrit). [☕️, Apache License 2.0].
• Review Board ★1504 - An extensible and friendly code review tool for projects and companies of all sizes. [🐍, MIT License].

This it not the first list of free / open source software. Here are some other lists:

• Awesome-Selfhosted ★149122 - A list of Free Software network services and web applications which can be hosted on your own servers. [Other license].
• AFS ONE - Free Software Publisher Directory.
• Awesome Free Software ★1 - Your "yellow pages" of Enterprise Free Software Publishers, their products and success cases. [Unknown license].
• Awesome open-source alternatives to SaaS ★13941 - Awesome list of open-source startup alternatives to well-known SaaS products 🚀. [🐍, MIT License].
• Guide des solutions open source (in French)
• SILL - Catalogue de référence de logiciels libres recommandés pour l'ensemble de l'administration (in French)
• Comptoir du Libre (in French)