API Virtualization

API Virtualization


Testers facing many obstacles to rapidly and completely finish testing an application. One of these obstacles is access to third party or even internal APIs that are called from the application undergoing testing. Access to these APIs could be restricted if:

  • These APIs are in production and testing against them creates an unreasonable risk.
  • These APIs are owned by a third party and only the third party only allows testing under restricted or limited circumstances.
  • The APIs are not always available due to physical location or presence. Trying to test an application designed to interface with a car is difficult, for example, if the car is not present.
  • Injecting errors into these APIs for testing is incompatible with the services operation.

To overcome these obstacles, testers are virtualizing the APIs required for an application creating an API sandbox. By virtualizing the APIs, testers can work against simulated production environments and have unlimited access to the services thereby enabling rapid completion of testing. 

The use cases for virtualized services are many.  A weather data provider might make their API available for developers to use to integrate weather data into their mobile application. Rather than making the actual API available for testing, the weather service might virtualize the API making a simulated service available. By virtualizing their API, the weather data provider enables developers to create great apps while removing the risk that application testing might take down the core weather service.In another example, an internal banking application might virtualize a wire transfer API so the bank’s developers can test calling the virtualized API without actually initiating wire transfers.

The Internet of Things (IoT) is a perfect place to apply virtualization, both of device interfaces and common service and API endpoints. If you don’t have a device to test, simply virtualize the typical responses and continue developing or testing. If you want to simulate failure of a shared device hub, simply virtualize the common endpoint and modify its behavior to see the effects on devices.


Ready! API as a platform gives you complete control over simulating APIs from either your local computer or from hosted collaborative environments. ServiceV allows you to design and control virtual APIs (Virts) while VirtServer allows you to deploy and manage Virts on a shared team server.

With SmartBear's approach to API virtualization:

  • Developers can stand up Virts in place of simple mocks that scale poorly or are too complex to manage by other teams.
  • Testing teams can use Virts to overcome 3rd party access problems, rate limits, and challenges in data manipulation requirements.
  • Integration teams can leverage Virts as part of their A/B testing and remapping strategies.
  • Managers and directors benefit from teams that can develop and test in parallel to deliver high quality services on time.

ServiceV represents a powerful yet easy to adopt approach to accelerating the delivery lifecycle for API teams and enterprises.

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