MQTT¶

ChirpCloud runs an MQTT broker per deployment. You connect with credentials from the portal, scoped to one application.

Create a credential¶

In the portal, MQTT credentials → Create credential for an application (up to 5 per application, while your workspace is active). You get a username (also the client ID) and a password; the password is shown once and ChirpCloud does not keep it. The portal lists each credential with its application ID and exact topics. Revoke there disconnects it for good.

Note

The ChirpStack UI's MQTT Get certificate button is not supported: use portal credentials.

Connect¶


Broker	`mqtt.chirpcloud.co.uk:8883` (TLS, publicly trusted certificate)
Client ID	must equal the username you were given
Subscribe	`application/<application_id>/device/+/event/+`
Publish downlinks	`application/<application_id>/device/<dev_eui>/command/down`
Retain	not supported: a retained publish disconnects the client
Sessions	persistent sessions expire after 1 h offline
Packet size	64 KiB max

Anything else (other applications, gateway/radio topics, publishing events) is refused.

Example¶

The broker's certificate is publicly trusted, so no CA file is needed: mosquitto 2.x uses TLS with the system trust store on port 8883, as do most MQTT clients once TLS is switched on.

mosquitto_sub -h mqtt.chirpcloud.co.uk -p 8883 \
  -i "$USERNAME" -u "$USERNAME" -P "$PASSWORD" \
  -t "application/$APPLICATION_ID/device/+/event/+" -v