Hi @m.daviau,
It looks like this may be an issue with the JSON parser in the Basic Python 3 environment. Does this occur in the Full Python environment?
In general, however, Anvil should be able to cope with application/json payloads that the parser barfs on. I’ve made a change, which will go live in the next few days, which won’t attempt to do built-in JSON parsing unless and until you access the body_json attribute.