All receivers report their data to a central MQTT broker, which feeds the live map at opentrafficmap.org.

• The current connection string (host and port) is defined in the firmware: its-g5-receiver-firmware/main/config.c
• Publishing requires no username or password.
• Every node identifies itself by its node name — by default the Ethernet MAC address of the ESP32 (e.g. aabbccddeeff). We are happy to replace it with a friendly name in our database; see Node Registration.

Each node publishes under its/nodeXXX/…, where nodeXXX is the node ID — currently simply an ascending number. You can find your node's ID in the self-service portal (see Node Registration):

To subscribe to all messages of a node, the wildcard its/nodeXXX/# should work as well by now.

The self-service portal shows credentials that allow you to subscribe to the messages of your own node — see Node Registration. You can use any MQTT client; a list of clients for Linux, Windows, and macOS is in the FAQ.

• the received raw C-ITS frames (CAM, DENM, MAPEM, SPATEM, IVIM — see C-ITS)
• node telemetry and status information

If you built your own receiver, there are several ways to get your data onto the broker — see Transmission Methods.