Ask HN: Options for hosted public API service?

I'm exploring options for a public API service. I was going to with Firebase because I heard I could create a public API there, but after some research it requires a public key to use the API.

I'm looking for a platform or service where I can host my API endpoint that doesn't require the user to use any authentication tokens.

Currently all I'm really aware of is Huroku and Digital Ocean. Any other good options out there I should take a look at to weigh my pros and cons?