Spectrum 2 is a free, open-source instant-messaging transport that bridges XMPP servers with other IM networks. Self-hosted, C++ based, no licensing fees.
Spectrum 2 is an open-source instant-messaging transport and gateway. It sits alongside an XMPP (Jabber) server and translates messages so that users on one network can communicate with contacts on other, otherwise incompatible IM networks. It began life as the original Spectrum transport built by developer Jan Kaluža and was later rewritten as Spectrum 2 to support a more modular set of frontends and backends.
This is a self-hosted, developer-oriented open-source project rather than a hosted consumer product. It is distributed through GitHub under the SpectrumIM organization and is documented at spectrum.im.
Disambiguation is important here: Spectrum 2 (spectrum.im) should not be confused with the separate Spectrum community chat and forum platform (spectrum.chat) built by the withspectrum team, which GitHub acquired in 2018 and subsequently shut down, moving the service to read-only in August 2021. The two products share only a name; they were built by different teams for different purposes.
Spectrum 2 functions as an XMPP frontend paired with pluggable backends for different IM networks, letting a self-hosted XMPP server exchange messages with users on other systems. It supports both gateway mode and server mode deployment, Docker-based installation for easier setup, and a modular architecture that separates the frontend (how clients connect) from the backend (which network is being bridged).
Spectrum 2 is free, open-source software with no licensing fee. Because it is self-hosted, adopters bear their own infrastructure and maintenance costs rather than paying a subscription to a vendor.
No. Spectrum 2 at spectrum.im is an open-source XMPP instant-messaging transport and gateway. The separate Spectrum community-chat and forum platform at spectrum.chat was built by a different team, acquired by GitHub in 2018, and shut down in 2021. They only share a name.
Yes. Spectrum 2 is free, open-source software that you self-host; there is no vendor subscription fee.
It acts as a transport and gateway that lets an XMPP server exchange messages with users on other, otherwise incompatible instant-messaging networks.
Public release history shows its most recent tracked version was 2.2.1 in mid-2023, suggesting slower recent development activity. Anyone considering it for production should verify current maintenance status directly on the project's GitHub repository.
The codebase is primarily C++ and C, with smaller amounts of Python, Objective-C++, and Lua.
Yes. Spectrum 2 is self-hosted software that runs alongside an XMPP server rather than a hosted cloud service.
It originated from work by developer Jan Kaluža and is maintained as an open-source project under the SpectrumIM organization on GitHub.