Backend: MQTT(s)

Also, you can enable relaying data to MQTT server:
It also supports MQTT client authentication via SSL by enabling the upload of a client certificate and its associated private key, ensuring secure and verified client-server communication. You can use a server SSL Certificate if you want to be independent of public Certificate Authorities (CAs) or if you have deployed a self-signed certificate on the HTTPS server, giving you greater control and customization over your security infrastructure: