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Archive for December 2016

Web API versioning in real world applications

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Once you have published your API it is set in stone. Customers who use your API expect it to not change. Otherwise their code may fail due to changed contract or behavior. But requirements will change and we need to figure out a way to evolve API without breaking existing clients. So every time when a breaking API change occurs you need to release a new version of API. That does not mean you need to support all versions forever. But you need to get rid of old versions of API with some care so customers have an idea how to move to a newer version of API.
In this post I am going to discuss how Web API versioning affects entire application and provide some recommendations how to organize source code to maintain different versions of API.

Example project can be downloaded here.

Introducing test application

In order to illustrate API versioning strategies we are going to develop a simple Web API for retrieving tasks. A task contains Name, Description, Owner and task state attributes: IsStarted and IsFinished. Each task belongs to particular Project which is barely a container of tasks. Application consists of three layers:

  • Domain layer that includes Task and Project definition
  • Data access layer that defines TaskRepository class. TaskRepository uses domain classes in serialization.
  • Distributes services layer defines DTO’s used by TaskController


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Written by vsukhachev

December 12, 2016 at 10:37 am

Posted in Development

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