Ask HN: How do you do end-to-end testing of your API?

At my company, we have a growing number of services written in golang. We are looking to standardize the automated end-to-end tests across the different services. I would love to hear how you handle end-to-end testing in your service that is accessible through http endpoints. Bonus points if you have also dealt with internal gRPC endpoints. I only mention golang if you happen to use something specific to golang development but the end-to-end testing solution does not have to be limited to golang.

Thanks!