I’m quite sure it simply cannot do that. The documentation is quite specific about the payload that is posted to the URL:
The integration will post data in the following format: […]
See also:
- HTTP integration with Azure Functions (testing) for a possible “serverless” solution using Microsoft Azure
- The Labs story Serverless TTN POST Adapter for a similar solution using AWS Lambda
- Sensor node -> LoRaWAN gateway -> TTN -> ThingSpeak -- how? for earlier attempts and workarounds
- Make TagoIO use timestamp from application payload instead of metadata - #2 by arjanvanb for an example using Pipedream