TinyGSM

A small Arduino library for GSM modules that just works. This library is easy to integrate with lots of sketches that use Ethernet or WiFi. PubSubClient (MQTT), Blynk, HTTP Client, and File Download examples are provided. Arduino GSM library uses 15868 bytes (49%) of Flash and 1113 bytes (54%) of RAM in a similar scenario. TinyGSM also pulls data gently from the modem (whenever possible), so it can operate on very little RAM. Now, you have more space for your experiments. TCP (HTTP, MQTT, Blynk, ...) All modules support TCP connections. Most modules support multiple simultaneous connections. TCP and SSL connections can usually be mixed up to the total number of possible connections. Many GSM modems, WiFi, and radio modules can be controlled by sending AT commands over Serial. TinyGSM knows which commands to send, and how to handle AT responses, and wraps that into the standard Arduino Client interface.