MongooseIM review 2026: Erlang Solutions' open-source XMPP messaging server for enterprise chat at scale. See features, pricing, pros, cons and alternatives.
MongooseIM is an open-source XMPP instant messaging server built by Erlang Solutions, a London-based Erlang and Elixir consultancy founded in 1999. Written in Erlang — a language designed for telecom-grade fault tolerance and concurrency — MongooseIM targets large, enterprise-scale messaging deployments rather than small hobbyist chat servers. Its first stable release shipped in July 2012, evolving from the established ejabberd XMPP server codebase.
The project is aimed at organizations that need to run their own chat infrastructure at scale — telecoms, messaging apps, gaming platforms, and IoT products — while staying on the open XMPP standard rather than adopting a proprietary, vendor-locked chat API.
MongooseIM clusters horizontally across machines and data centers to support millions of concurrent users, and it accepts connections not just over native XMPP but also REST API, WebSockets, Server-Sent Events, and BOSH (HTTP long-polling), making it accessible from web, mobile, and IoT clients.
Messaging features include one-to-one chat, multi-user group chat, an inbox feature, delivery and read receipts, and seamless multi-device session handling. MongoosePush adds native iOS and Android push notifications, and the server can serve as the signaling layer for real-time voice and video call setup, plus support for end-to-end encryption and GDPR-aligned data handling.
MongooseIM itself is fully open source and free to download, self-host, and modify from its GitHub repository. There is no license fee for the software.
Erlang Solutions monetizes the project through professional services: 24/7 production support contracts, custom feature development, and consulting for teams that want to run MongooseIM at scale without building Erlang expertise internally. Pricing for these services is quoted per engagement and is not publicly listed.
Yes, MongooseIM is open-source software that is free to download and self-host. Erlang Solutions separately sells paid support and professional services for production deployments.
MongooseIM is developed and maintained by Erlang Solutions, a London-based Erlang and Elixir technology consultancy founded in 1999.
MongooseIM implements XMPP (Extensible Messaging and Presence Protocol), an open, federated messaging standard, and also supports REST, WebSocket, SSE, and BOSH client connections.
Yes, it is designed to scale horizontally across clustered machines and geographically distributed data centers to support millions of concurrent users.
Yes, via its companion component MongoosePush, which delivers native push notifications to iOS and Android devices.
Common alternatives include other open-source XMPP servers like ejabberd and Openfire, and proprietary chat-infrastructure APIs such as Sendbird, PubNub, Twilio Conversations, and Stream Chat.