# Why APIs Need Versioning — REST API Design

Source: https://www.geekswithgeeks.com/en/restapi/api-versioning-why

> Evolving an API without breaking clients who are already using it.

## You don't control the client

Unlike an internal library, you can't force every consumer to upgrade at once — mobile apps sit on old versions for months, third parties integrate once and forget. A breaking change to a shared endpoint breaks all of them simultaneously.

## Additive vs breaking

Adding a new optional field or endpoint is usually safe without a version bump. Renaming/removing a field, changing a type, or changing status codes is **breaking** — that's what versioning exists to manage.

## Version from day one

Even a `v1` prefix with no plans for `v2` costs nothing now and saves a painful migration later once real clients depend on you.