Open-source alternatives to Revolt

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

Whitebophir is a collaborative whiteboarding application designed for real-time visual collaboration. It enables multiple users to brainstorm and create content together on a shared virtual canvas using freehand sketching, geometric shapes, and text labels. The platform focuses on private workspace management, allowing the creation of restricted boards via unique URLs and token-based access control to manage editing permissions. It integrates real-time state synchronization for drawing updates and a built-in chat system for text communication between collaborators. The workspace includes too

RetroShare is a Free and Open Source cross-platform, Friend-2-Friend and secure decentralised communication platform.

This project is a self-hosted, cross-platform instant messaging platform featuring a Go backend and a protobuf-based messaging server. It provides a unified communication suite with native clients for iOS, Android, and web, utilizing gRPC and Protocol Buffers for efficient data exchange. The system is distinguished by an extensible chatbot framework that allows for the integration of automated bots and plugins via standardized service interfaces. It supports high-availability clustering with sharded load distribution and a pluggable database backend to ensure reliability and flexible data per

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

Free API for outgoing SMS

This project is a decentralized, privacy-focused messaging platform designed to eliminate reliance on central servers and persistent user identifiers. By utilizing a metadata-minimizing protocol, it ensures that all communication remains end-to-end encrypted and that user identities are stored exclusively on the local device. The architecture relies on relay-based message routing and identity-free network addressing to maintain data sovereignty and prevent the correlation of user activity. What distinguishes this platform is its commitment to traffic isolation and anonymity. Each conversation

Papercups is an open-source live chat platform and self-hosted customer messaging system. It provides a real-time communication infrastructure consisting of an embeddable web widget for customers and a containerized administrative dashboard for support teams. The platform features an omnichannel messaging hub that aggregates and normalizes conversations from email, SMS, and third-party chat channels into a single unified stream. It also includes a framework for deploying automated FAQ chatbots to handle initial inquiries and a real-time session monitoring tool that allows agents to view a use

Synapse is a decentralized communication server implementation that enables real-time messaging and data exchange across the global Matrix federation. It functions as a homeserver, allowing operators to host their own nodes while maintaining control over personal data and user identity within a distributed network. The server utilizes a federated messaging protocol to exchange messages and user data with independent servers, ensuring consistent state across the network. To support high-traffic environments, it employs a distributed service architecture that offloads tasks to independent backg

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

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Android app for ntfy.sh

Centrifugo is a self-hosted real-time messaging server that provides infrastructure for scalable notifications, a publish-subscribe message broker, and a language-agnostic WebSocket gateway. It allows for the delivery of instant messages and data streams to concurrent users via WebSockets and Server-Sent Events. The system functions as a communication layer that separates network transport from backend business logic. It supports distributed messaging clusters using Redis for coordination of presence and message delivery across multiple server nodes. The project covers channel subscription m

Eyevinn Open Intercom is a low latency, web based, open source, high quality, voice-over-ip intercom solution. It is designed to be used in broadcast and media production environments, where low latency and high quality audio are critical. The solution is built on top of WebRTC technology and…

Apprise is a notification library and command-line utility that provides a unified interface for sending alerts to a wide range of messaging, email, and push services. It abstracts the complexities of diverse third-party communication APIs, allowing users to dispatch notifications through a single, standardized method. The project utilizes a connection-string-based routing system to map notification requests to specific service drivers. It features a modular plugin architecture that supports the integration of new messaging platforms and custom notification hooks. Users can organize service e

ntfy is a self-hosted messaging infrastructure that provides a lightweight platform for sending and receiving real-time notifications. It functions as a topic-based pub-sub server, allowing users to publish and subscribe to message channels using standard HTTP requests. By bridging server-side events with native mobile and desktop clients, it enables the delivery of alerts across various environments through a unified communication layer. The project distinguishes itself by offering a complete, private notification ecosystem that includes persistent message caching and robust access control.

MongooseIM is Erlang Solutions' robust, scalable and efficient XMPP server, aimed at large installations. Specifically designed for enterprise purposes, it is fault-tolerant and can utilise the resources of multiple clustered machines.

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

⚡ The future of programmable SIP servers.

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

A chat server with OAuth2 authentication, persistent and searchable history, video and audio, markdown formatting, private and public rooms, stars, votes, embedded games, and many other features

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

An app for creating push notifications for new messages posted to gotify/server.