You can connect your devcies using any of the 3 protocols compatible with thethings.iO (HTTP, CoAP, MQTT). Each of them has its pros and cons.
HTTP is over TCP and there are lots of libraries implementing it. If there isn't a language for your platform, it is very easy to implement as it is just writing characters on the TCP socket. However, it is the protocol that introduces more overhead.
CoAP is over UDP, designed especially for IoT and introduces minimum overhead. While we don't support CoAP with DTLS yet, contact us if you need the feature.
MQTT is over TCP and is best suited for long term subscriptions. MQTT is also lighter than HTTP, but it's not possible to reproduce all the features supported by the other protocols (like reads) with it.
Updated 3 years ago