Handling JSON (error) response and passing to Contact Form 7

It’s typical for APIs to return a response. Would be nice to be able to handle is somehow.

Right now I’m wondering how to handle errors, for example:

{“error”:”[\”Email is not valid\”]”,”status”:400}

I would like to show Contact Form 7 posting as not succesful and at least show this error message to the user. Of course I can have front-end validation, but the error messages and responses could be various.