API Versioning

After creating an API, you might want to change its behavior, authentication mechanism, resources, throttling tiers, target audiences etc. at a later point in time, depending on new business or technical needs of the organization. But, you cannot do these changes to an API that is already published and has users plugged into it. A published API should be fixed. The way to modify it is by publishing a new version of the API with changes. The general practice is to encourage users to adopt the new version by depreciating the old API after giving them time to test their applications with the new API. 

The API Manager facilitates API versioning as part of API life cycle management. The steps below show how to create a different version of an existing API.

1. Log in to the API Publisher as a user who has the creator role assigned. For more information on creating users and assigning roles, refer to section User Management. 
2. Available APIs shows in the All APIs window of the API Publisher. Click on the API that you want to create a version of. 
3. The API's Overview tab opens. Create a copy of the API using the Copy button in the Overview tab. For example,
   
     
4. It opens a window allowing you to specify a new API version. Generally recommended format is version.major.minor. For example, 1.0.0.
5. The newly-added version appears in the All APIs window of API Publisher.

After creating the new version, a user who has the publisher role assigned can publish the API. At the time you publish it, you can select the Deprecate Old Versions option to automatically deprecate all previous versions of the API. For instructions on publishing an API, refer to section Managing an API Life Cycle.