Engineering at Clearbit
At Clearbit, we pride ourselves on making it possible for anyone to get started with our APIs and data within minutes. Part of this means we provide a free trial to users that sign up at clearbit.com. A single trial account can't do anything particularly troublesome, but en-masse it's possible to create traffic and usage patterns we'd consider abusive at a free tier. Every night around 10 pm PST, a pattern of sign-ups were appearing that featured suspicious emails from disposable email provider