Versioning an API endpoint Using an API is great, but what happens when your business already has clients, and your product communicates via an API, what should you do to evolve your API? Whether it’s a server-to-server, or an app-to-server communication, the best way to evolve your APIs is to version them, this will help you to prevent breaking changes between the communication, and believe me, you don’t want to have angry clients knocking at your door.