The Design of Web APIs

9 Evolving an API design

This chapter covers

• Designing evolutions to avoid breaking changes
• Versioning APIs to manage breaking changes
• Designing extensible APIs to limit breaking changes

In the previous chapters, you learned how to design APIs that provide features or goals that make sense for their users. You also learned how to design user-friendly and secure representations of these goals. Once all that work is done, is that the end of the API designer’s job? Not at all! It’s a new beginning.

An API is a living thing that will inevitably evolve, perhaps to provide new features or enhancements to existing ones. To design for such evolutions, you can reuse the same skills you have learned up to this point—but designing evolutions requires ...