A Crash Course in API Versioning Strategies

Developing an API involves a lot of work, from planning to implementation. It's crucial to have a clear and easy-to-understand versioning strategy to avoid confusing developers. In this week's issue, we'll explore different versioning strategies for APIs.

We'll begin by examining the reasons for versioning APIs and when it's necessary to release a new version. We'll also investigate various versioning strategies, how to label API versions, and methods for gracefully retiring outdated API versions.

So, without further ado, let’s jump right into it. 

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Why Version APIs? 

As we add new features to our API, fix existing issues, or change how our API works, we need to deliver these changes without disrupting our users. Let’s understand this with an example.

Imagine we have an API for weather forecasts. Thousands of websites use it to build dashboards and other applications.

Let's say we want to change the data contract of our response object. This could involve renaming a field, adding a new one, or changing the entire data contract. If we change an existing field name, our users’ applications might stop working or start throwing errors. 

To fix this, we'd have to ask all our users to update their applications to work with our newest changes. If this happens often, our users will be frustrated. 

Versioning solves this problem. When we want to release a breaking change, we upgrade the version of our API. We release it in a way that lets users choose when to accept the changes. 

Once clients start using our API, they rely on it to work as originally designed. If we make changes or release new versions without considering our clients' needs, it could cause problems. That's why it's important to version our API and give clients the choice to upgrade when they're ready.

That's why designing for change is essential for APIs. We should use versioning to deliver changes to our users in a clear, consistent, and well-documented manner.

When to Version APIs?