What is API Versioning? - Standards & Strategy

API Versioning - What is it?

It is a procedure that implicates making operational and structural changes to the APIs so that they can become adaptable and suitable to the growing and altering requirements of the customers. 

With time, the earliest API structure and functionality tend to evolve as a bygone element. In order to keep an API time-relevant, API developers must fix the bugs, boost the functionality, and add new capabilities to the existing APIs. 

Even though it’s a tedious task to do as it concerns some API structural changes, it’s crucial to make sure the API is capable to handle the present-day requirement of the consumers.

Some of the key things to keep in mind during API versioning are:

• Patching any consumer-side contradictions
• Confirming that no breaking change with the code modification is hampering the end-users
• Supplying enough time to consumers to integrate the asked changes

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When to create a version of the API

By far, the thumb rule to launch an API version is whenever one seems the existing version is obsolete. However, certain situations demand API versioning for sure.

Launch an API version when:

• Any, minor or major, API fields and routing outings are done post the API release
• API payload structures are changed at any level  
• Any API endpoint is eliminated to fix the design flaws or get rid of a faulty HTTP implementation

Any of the above changes in API asks for versioning so that the products, developed using the early APIs, won’t face severe breaking changes.

In addition to the above reasons, versioning is a must when developers will add new API endpoints or parameters to the API responses. However, both these situations won’t ask for a completely new version release. Only minor updates are enough.

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Why Should you do Versioning?

One might think why to get interested in such drab REST API versioning or anything similar. Well, using the version API is crucial in two aspects.

1. ‍Disruptive change

Adjusting any code or primal API structure will direct to breaking changes on the consumer side as well. If one doesn’t adopt the approach, the end-user might compel the consumer to make changes in their applications as well.

Here are some modifications that fall under the classification of disruptive changes:

• Altering the original request/response format type
• Revising the data type of a property or the property name completely
• Addition of a new essential field, e.g. a ‘required’ header
• Eliminating any pre-defined response property like description details

All these changes will have a direct impact on the apps designed using the original APIs. If the new version of API isn’t launched, all the produced applications will go through intense operational and structural flaws. Hence, API developers must adopt an API versioning strategy. It’s also required from the API security point of view as unaddressed or revamped destructive changes may weaken the security.

2. ‍Change management in the API

API clients shouldn’t be allowed to make any modifications in the API. Any big or notable change should be handled through versioning only. Change management, here, ensure that it happens.

The process is feasible to avert any breaking API changes that you can expect. It revolves around the below principles:

• Providing ongoing support for the present API properties/end-points
• Providing fresh end-points or properties instead of modifying the previous one
• Carefully terminating the outdated end-points/properties

Adhering to these principles help reduce the efforts invested in versioning and make it simpler to deploy.

The API Contract

Out of all the API versioning best practices, creating and updating an API contract is the most crucial one. By API contract, we indicate a legal, detailed, and valid agreement between the API developers and end-user. The document, electronic or paper-based, defines the API functionality, services offered by the API developer, the responsibility of the end-users while using the API, and many other things.  

Basically, it’s a way to encourage transparency between the API producer and consumers. It also concerns tracking API changing and updating consumers about the implications of those modifications. Speaking of the scope of the API contract, it covers API media types for all the leading API types, including REST API. However, URIs are not mentioned in it.

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Several types of API versioning

It ought to be of various kinds, as API usage is not one type. Have a look at the standard varieties developers use the most.

• ‍Query Parameter Versioning

As the name denotes, this type concerns mentioning the API version with the help of a query variable. It’s effective and easy to implement. With the help of this technique, you can define the default version of the API that’ll remain active until a new one isn’t defined or declared.

• ‍URI Versioning

It involves mentioning the API’s version details in URI. It’s loved because of its unmatched effectiveness and easy implementation. One has to introduce the ‘v’ prefix in the URI path.

The only thing that you need to bring into action is setting API endpoints every API developer does eventually. It’s perfect on most of the fronts but disappoints by causing a major API design flaw. It forces every URI to feature a distinct resource that causes a huge URI footprint.  

API developers use this method to announce the present app version. The endpoint version isn’t defined by it.

• ‍Custom Headers Versioning

It permits you to declare the version type API version in header itself, letting you complete the process fast. The version number is used for the job. It doesn’t involve adding any filler in the URI that makes it a to-the-point API versioning.

Conclusion

We learned a lot in the post. Let’s do a quick refresh:

• API versioning refers to modifying the API version transparently.
• It has many kinds and types.
• Following this process is a must whenever any disruptive or breaking changes are done in the API.
• API change management focuses on adding new capabilities rather than completely changing the previous one.

Although this learning is the base of API versioning standards, they tend to change or modify a bit with the consumer demand. API evolution is a complex task and needs to be achieved with full perfection. While you do so, don’t get diverted from API protection. It has to be strong and sound to keep API usage risk-free.