a daemon that facilitates communication over Signal. It is unofficial, unapproved, and not nearly as secure as the real Signal clients
Signal does not offer any sort of official API. Unlike traditional messaging applications, the Signal server expects the client software to perform encryption and key management. signald handles all of these client-side requirements and exposes a plain-text API which can be easily used by developers to build custom Signal clients.
Documentation is available on signald.org
When started, signald will create a unix socket file which clients connect to. Clients software uses this socket file to interact with signald. Most users will want to use an existing client. Developers wanting to write their own clients should consult the list of libraries. Alternatively, build your own library: the socket protocol is documented in a machine-readable format that can be used to generate libraries. For details, see the Protocol Documentation page.
Issues and MRs are accepted via GitLab.com. There is also an IRC/matrix channel. if you have a question, open an issue or come by the channel. Some aspects of signald aren't well documented, don't be afraid to ask "stupid" questions.
This software is licensed under the GPLv3. See LICENSE file in this repository.