Influxdb2 http alert documentation

[shiftsystems]

I am trying to create alerts that go to either zammad, gitlab, or matrix via the http alert endpoint. I have issues tying to figure out how messages are sent. there is no place to put json data or headers directly and I am not sure how the message field is sent via http. I tried finding documentation but I all I found was this.

Create notification endpoints | InfluxDB OSS 2.6 Documentation