API Versioning and Testing


  • What is API Versioning?
  • Why API versioning is required?
  • When is API versioning performed?
  • How do you achieve API versioning?
  • Testing API versioning scenarios
  • Downsides of API versioning
  • Real world examples

What is API versioning?

It is impossible to ignore the focus on APIs and their function in advances in technology. One of the most popular and crucial subjects to debate and comprehend is API versioning. Businesses must continually iterate to improve their solution offerings as technology advances in order to satisfy the always-changing needs of their clients. Let us start by understanding what is API versioning? The process of generating and maintaining various API versions in order to maintain backward compatibility while making changes to the API is known as API versioning. It enables programmers to modify the API without disrupting already-in-use integrations that rely on the API.

Versioning of APIs is crucial because changes to the API may affect how clients utilize it. Any modifications to the API’s behavior may cause a breaking change if a client depends on that behavior. Clients can utilize an older version of the API up until they are ready to switch to a newer one thanks to versioning.

Why is API versioning required?

Support for legacy integrations: APIs are used to exchange data and interact with multiple applications. These integrations work with a specific version of an API. If the API provider updates or changes the API version the integrations will fail and applications will break. By versioning the API, developers can continue to support these legacy integrations while making changes to the API.

Flexibility for clients: Not all customers would like to change their existing setup or integrations immediately for various internal reasons. Versioning of APIs provides an opportunity for businesses to upgrade to the newer version of APIs at their own pace.

Error handling: When an API changes, it can result in unexpected behavior and errors for clients who rely on the API. By versioning the API, developers can provide clients with clear and consistent error messages, reducing the risk of unexpected behavior.

Improving API quality: Versioning allows developers to make changes to an API in a more controlled and structured way. Teams can test and refine new versions of the API before making them available to clients, ensuring that the API is of higher quality and more reliable.

When do you perform API versioning?

  • When renaming fields or resource paths
  • When you want to change payload structures to incorporate things like; changing an integral to afloat.
  • Removing parts of the API endpoints either to fix HTTP verbs, inconsistent design, or response codes.
  • If the protocol used by an API changes (e.g. from REST to GraphQL), this can potentially break compatibility with existing clients.

How is API versioning Achieved?

There are different approaches to API versioning, including:

URL versioning: In this approach, the API version is included in the URL, such as api.example.com/v1/resource. Clients can continue to use the older URL until they are ready to migrate to the newer version.

Header versioning: The API version is included in the HTTP headers in this approach. Clients can specify the version they want to use in the request headers.

Content negotiation: In this approach, the API version is negotiated between the client and server based on the content type requested. The client can request a specific version of the API, and the server will respond with the requested version.For instance, some clients like the data in standard HTML, whilst others prefer the data in standard text format. Some could require the data in JSON format, while still others may prefer XML.

Namespace versioning: In this approach, the API version is included in the namespace of the API, such as example.com/api/v1/resource. Clients can continue to use the older namespace until they are ready to migrate to the newer version.

Testing in API versioning Scenario

In addition to the standard test methodologies, all test approaches are usable in the API versioning situation. To verify the reliability of versioning, test engineers may need to spend more time on the tests listed below.

Testing the new API version: All of API’s design and functional specifications should be met by the new version. All the tests that we typically run on any API will be applied to the new version of the API. The new API version most certainly won’t feature any major functional changes and will behave the same as its predecessor.

Version compatibility testing: New API versions are checked/tested against all the existing integrations. This involves testing the new version of the API against different clients to ensure that it works as expected.

Interoperability testing: Customers of enterprise solutions have the option to upgrade either the frontend, the backend, or both. Interoperability is crucial for testing in these situations. The data should still be rendered regardless of the UI and API versions that are being used.

Performance Testing: Technological improvements do not always translate into better performance; nonetheless, if the new API version responds more slowly than the one it replaces, users can decide not to upgrade at all.

Downsides of API versioning

API versioning can have several downsides, including:

  1. Compatibility issues: Different versions of the same API can be incompatible with each other, causing issues for users who rely on specific features or functionalities of a particular version.
  2. Complexity: Managing multiple versions of an API can be complex and time-consuming, as it requires developers to maintain and support each version separately.
  3. Fragmentation: Multiple versions of an API can lead to fragmentation of the user base, making it more difficult to build a cohesive community around the product or service.
  4. Increased costs: Supporting multiple versions of an API can be expensive, as it requires additional resources to maintain and support each version.
  5. Confusion for users: Users may be confused about which version of an API to use, leading to frustration and potential loss of business.
  6. Security risks: Older versions of an API may be more vulnerable to security threats, leaving users and their data at risk.

Real-world scenarios of API versioning

Google Maps API can be used to integrate Google maps into applications. The current version of the Maps API is v3, and the URL for this version is https://maps.googleapis.com/maps/api/js?v=3.

Twitter RESTful APIs that allow developers to access and interact with Twitter’s data. The current V2 version URL is https://api.twitter.com/2/.

Interested to get your hands around various versions of API? checkout Postman workspaces — https://www.postman.com/explore


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