Once the API gets to the stage where you need authentication, access controls, blocking access, proper rate-limiting or billing, you have outgrown the "email ad

Once the API gets to the stage where you need authentication, access controls, blocking access, proper rate-limiting or billing, you have outgrown the "email address in request" method. After all, the abuser might not be a former developer, but anyone in the world who knows your email address. But for a first experimental API, it's much better than having no info on who your users are besides an IP address pointing to AWS. And logging API requests to a text file and doing analytics manually with grep is much faster than setting up developer accounts.