> This makes sense. These keys were designed as project identifiers for billing, and can be further restricted with (bypassable) controls like HTTP referer allow-listing. They were not designed as authentication credentials.
Can't you just run up a huge bill for a developer by spamming requests with their key? I don't see how this wasn't always an issue?
Keys could have certain restrictions [1] such as HTTP Referer, which meant you couldn't just embed a map on your website and charge a different website for the views.
Not perfect protection of course - an attacker could spam requests with all the right headers if they wanted to - but it removes one of the big motivations for copying someone else's API key.
Can't you just run up a huge bill for a developer by spamming requests with their key? I don't see how this wasn't always an issue?