Application and formatter
Create an application for the site. Add a payload formatter per device type, using the decoder file from the kit. Uplink formatters should return the fields listed on the matching decoder page — wet and zone for rope leak, level for the submersible kit, moisture and EC for soil, temperature_c for the needle probe.
EU868 and US915 frequency plans must match the hardware. A US915 device on an EU868 application will not join. Fix the frequency plan before you edit the formatter.
Join
Use OTAA. DevEUI, JoinEUI, and AppKey come from the kit paperwork, not from a guessed template. After join, the first uplink should resemble the factory functional-test record. If the bytes match and the formatter output does not, the formatter is the wrong model.
Store the device name as the room, tank, or plot name. A DevEUI-only list is accurate and still useless to the person on call.
Downstream
Webhooks, MQTT, and storage integrations all consume the formatter output. If TTN shows decoded fields and your database does not, the bug is downstream. If TTN shows hex only, the formatter did not run or threw. Read the formatter error before you RMA the sensor.
Public community networks and private The Things Stack instances use the same formatter idea. Confirm you are looking at the server that actually received the gateway traffic.
Related pages
FAQ
Can I use the ChirpStack codec unchanged on TTN?
The field contract is the same. The paste location and function signature follow TTN's payload formatter, not ChirpStack's codec hook. Use the file shipped for TTN if both are in the pack.
Why does join fail?
Check frequency plan, OTAA keys, and gateway coverage. A formatter cannot fix a device that never joined.
Which page documents PS-210 fields?
The PS-210 decoder page. This page only explains where the formatter lives on TTN.
Is TTN required?
No. ChirpStack and other network servers that accept a payload decoder are in scope. TTN is the public-network path.