Take in SMS from Twilio as an HTTP GET and pipe it to XMPP, and vice versa.
A daemon that implements the Signal protocol. You have to interact with it through the UNIX socket it opens. You can either register a brand-new phone number for this daemon or add it to the one you already have.
In the AUR.
An implementation of Textsecure/Signal in Golang as a CLI tool. Can send and receive one-to-one and group messages.
A web application that sits in front of a command line Signal client that lets you send messages from a web browser. Seems to also have a REST API. Requires a second phone number to set up an account, it's not an extension to an existing Signal setup. Looks like all-Docker-all-the-time but it looks like you can also run it as a system service (a systemd .service file is in the docs, and it says nothing about using Docker for that).
Interestingly, it's a couple of shell scripts.
A tool which interfaces with Signal on behalf of one of your devices to send text messages. Designed for use in scripts. Written in Java, in the AUR, I probably already have it installed on Leandra.
An openstreetmap app for android which keeps tabs on your GPS coordinates and shares your location in an anonymous fashion with a random Target ID and tracking code. Can share with chosen people or the public at large. Can transmit and receive data via SMS.
4481 links, including 318 private