Open-source alternatives to Asterisk

Jitsi Videobridge is a WebRTC compatible video router or SFU that lets build highly scalable video conferencing infrastructure (i.e., up to hundreds of conferences per server).

FreeSWITCH is an open-source software telephony switch that routes and processes voice, video, and messaging calls over IP networks using standard protocols such as SIP and RTP. It serves as both a call routing and switching engine and a programmable telephony API, enabling developers to build custom telephony applications with event-driven call control and media manipulation. As a SIP media server, it handles media streaming, transcoding, and conferencing, and functions as a unified communications platform integrating voice, video, messaging, and conferencing into a single switchable infrastr

The core of an open-source, distributed, highly scalable platform designed to provide robust telecom services

OpenSIPS is a GPL implementation of a multi-functionality SIP Server that targets to deliver a high-level technical solution (performance, security and quality) to be used in professional SIP server platforms.

Open Source VoIP Billing Solution http://www.astppbilling.org | Report a bug https://inextrix.atlassian.net/jira/projects

Official FusionPBX - A full-featured domain based multi-tenant PBX and voice switch for FreeSwitch.

Ricochet is an experimental kind of instant messaging that doesn't trust anyone with your identity, your contact list, or your communications.

Discourse is an open-source forum engine designed to facilitate long-form threaded conversations and community management. Built as a server-side application, it provides a structured, category-based interface for interactive online communities, supporting user authentication, moderation, and real-time content delivery. The platform utilizes a relational database to manage complex relationships between users, topics, and site settings. The application distinguishes itself through a modular architecture that allows for custom plugins and themes, enabling the adaptation of discussion spaces to

Element Web is a web-based communication client used for real-time messaging and collaboration via the decentralized Matrix protocol. It functions as an end-to-end encrypted messenger, a VoIP client for voice and video conferencing, and an interface for interacting with integrated bots and external bridges. The project distinguishes itself through a modular architecture that supports runtime module loading and external script imports to extend core capabilities. It provides extensive white-labeling options, allowing for the customization of application branding, visual themes, and the use of

A community discussion platform: Brings together the main features from StackOverflow, Slack, Discourse, Reddit, and Disqus blog comments.

BigBlueButton is an open-source virtual classroom software and meeting server designed for hosting real-time online teaching sessions. It functions as a WebRTC video conferencing platform and collaboration suite, providing a self-hosted environment for virtual classroom management and online course administration. The system distinguishes itself through specialized educational tools, including an interactive quiz engine, breakout room coordination, and live polling. It provides a comprehensive suite of collaborative assets such as a shared infinite whiteboard, real-time co-authored notes, and

Converse.js is an embeddable, self-hosted XMPP chat client that runs entirely in the browser. It communicates with XMPP servers using standard XML stanzas over WebSocket or BOSH transports, and provides end-to-end encryption through the OMEMO protocol with double ratchet algorithm and X3DH key exchange. The client is built on a plugin-based architecture that allows extending core functionality at runtime without modifying the client itself, and uses a DOM-based rendering approach with an event-driven message bus for internal coordination. The client manages message history through XEP-0313 Me

FreeScout is a self-hosted, open-source help desk and ticket management system built with PHP. It functions as a customer support platform that enables teams to manage shared inboxes and organize customer email conversations into tickets. The platform distinguishes itself as a multi-channel support dashboard that integrates customer relationship management and a knowledge base system. It provides tools for tracking detailed customer profiles and organizational records while offering a programmable interface to manage and expose support articles. The system covers a broad range of support cap

Chatwoot is a self-hosted, omnichannel customer support platform designed to aggregate messages from diverse social and digital channels into a single, collaborative team inbox. It provides organizations with full data ownership and control over their support infrastructure, ensuring strict logical separation of customer data through multi-tenant architecture. By centralizing communication, the platform enables teams to manage, route, and resolve inquiries within a unified workspace that maintains complete interaction history for every contact. The platform distinguishes itself through an eve

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Kaiwa is not maintained anymore. See active forks here: https://github.com/digicoop/kaiwa/network

Helpy is a customer support platform and omnichannel help desk designed to manage support tickets, knowledgebases, and community forums. It functions as a centralized hub that converts emails into trackable tickets and provides a web interface for support agents. The system includes an embeddable support widget for external websites that connects users to agents or AI chatbots. It also serves as a self-service knowledge base for hosting searchable help articles and as an identity integrator for connecting users to external providers via single sign-on protocols. The platform covers a broad r

Freenet REference Daemon

Openfire is an XMPP communication server and enterprise messaging platform designed for real-time collaboration. It serves as a communication hub providing instant messaging, presence tracking, and multi-user chat capabilities for organizational use. The server supports federated network routing via an XMPP federation gateway, allowing users across different domains to exchange messages. It is designed for high availability through server node clustering and multi-node synchronization to balance client traffic and ensure continuous uptime. The platform integrates with external directory serv

Berty is a peer-to-peer messaging application and framework designed for decentralized private messaging. It utilizes a distributed identity protocol and a decentralized database to enable end-to-end encrypted communication without relying on central servers, phone numbers, or email addresses. The project distinguishes itself through an offline messaging framework that uses Bluetooth Low Energy and multicast DNS for local device discovery. This allows peers to establish direct connections and exchange messages without internet or cellular data, using QR codes for secure contact exchange. The

A high-performance Internet Relay Chat (IRCv3) server for UNIX-like and Windows systems

Toxcore is a peer-to-peer networking library that implements a decentralized communication protocol for secure messaging and media calls without the use of central servers. It provides a core engine for establishing direct encrypted connections between devices using a public-key identity system where unique identifiers serve as both addresses and authentication keys. The project features a decentralized network architecture that utilizes a distributed hash table for peer discovery and Kademlia-based routing to locate participants. To maintain connectivity across restrictive network environmen

Flarum is a PHP-based community forum software designed for building and managing structured online discussion spaces. It functions as a self-hosted discussion forum and threaded discussion engine, providing a platform for users to create and participate in community conversations. The platform is designed as an extensible community platform, allowing for customizable forum development through the use of custom extenders to modify system behavior and features. The system includes capabilities for online community management and forum hosting, supported by a console interface for executing ad