- This is Microsoft.
- He returns Webhook success with a code 200 and plaintext 1.
- He returns Webhook failure with a code 200 and a string tells its endpoint returned error 400.
- the string didn't tell what exactly the error.
- Don’t be like Microsoft.
EDIT: Got a few details wrong since this happens a few months ago and this meme used to be on r/ProgrammerHumor. Also the proof: 
Wait til you hear about graphql..
What don't you like about graphql error handling? Whenever I've made a graphql api, I use the default errors as unhandled/system errors and payloads return handled error types.
It's a bit more boilerplate to wire up, but I find it smooth to build and use
Just making a point that it always returns a 200 even when it errors.
Fair point, that it does
Yup I'm with you. Once the boilerplate is in place, smooth sailing from there. What OP is showing truly is the worst though lol.