To be clear, it seems you have basic coercions (a la C, or ad-hoc polymorphism) but no general support for subtype polymorphism nor parametric polymorphism.
You also pay a nominal fee per ms of compute used when somebody uses an API you’ve built.
But you can get started for free - $5.00 of credits included that should cover up to 100,000 requests, if you’re really experimenting feel free to message our team (my email is in my profile here, I think).