RaspiSMS is a web application for sending and receiving SMS messages. You manage contacts and groups, build dynamic mailing lists or personalised messages, and run SMS campaigns, for example for an association. RaspiSMS provides the interface and the logic; the actual sending goes through an SMS provider with an HTTP API, through a GSM modem with a SIM card, or, with the SaaS version, through an Android phone running the RaspiSMS Relay app. The software is officially intended for Debian-based Linux systems and is installed as a .deb package.
RaspiSMS is free software under the GPL v3 and is offered from France by a sole trader. You can self-host it free of charge, or take the SaaS version, which according to the legal notice runs at OVH in France. Note that the messages themselves pass through the SMS provider you choose, such as OVH or Twilio, and that provider therefore determines where the traffic is processed.