In our specific case, we’re providing users query access to datasets supplied to us by channel partners; where these partners pay us to make this data available

In our specific case, we’re providing users query access to datasets supplied to us by channel partners; where these partners pay us to make this data available through our API, because it makes their own ecosystems more valuable for our service to be offered as a part of them. So, technically, our revenue is entirely independent of customers. Which is why free-tier users still benefit us: the more DAU our platform receives, the more our partners value it, and the more they’re willing to pay us to make their data available through it. And before you ask, no, we don’t give our customer data to our partners; all they get to know is DAU and API call count for their network. > Whats the purpose of "free-tier" API SaaS. Mostly? Giving people a taste without the friction of paying, so that they get hooked, and start paying later. Like how you can have one Heroku VM for free. Or how GCP gives you a free month of usage when you sign up. I can’t think of a direct analogy within the API SaaS vertical specifically; but a hypothetical analogy would be if Twilio gave N free credits on each sign-up. > Fraud implies that the alleged perpetrator is obtaining something unlawfully or unfairly. However if that thing is "free" then how could this ever be true. Our free offer is intended to give people a certain amount of credits to spend to try out the service. By registering multiple accounts, you get multiples of that promotional amount. And, in fact, by registering multiple accounts, you escape the rate-limiting we place on every account, to ensure QoS and prevent Denial-of-Service attacks against our service. So we prevent people from registering multiple accounts. Analogy: someone who sees a free sample display in a grocery store, and stuffs the entire display into their bag. And then camps out the display each day, taking the whole thing again the instant it gets restocked. While also going around to N other stores in the chain, camping them out as well. It may not be illegal, but it’s 1. unethical, 2. against the spirit in which the promotion was intended, and 3. screws all the other customers out of their opportunity to get the free thing, because you’re using up their “share.”