HTTP status codes in API

My recent testing (just for user lookup) showed that the keybase.io API always returns a 200 OK status code, even if a queried username does not exist or the requested fields are invalid.

I see that keybase returns a json object with an error message, however, wouldn't it also make sense to return an according http error code?

The issue names no repository file, test, or API entry point. Start by reproducing the user-lookup and invalid-field requests, then locate the endpoint handling their JSON errors. Done means the intended HTTP status behavior is decided and covered for both failure cases.

Written by the indexing model from the issue text.