API Simulator for Easy and Realistic API Simulations

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Applications Heavily Depend on APIs



It is common for an application to depend on the APIs of a dozen or more other applications and components.


These direct dependencies in turn have their own API dependencies, which may depend on even more APIs and so on...

api dependencies diagram

Problems with API Dependencies Hinder Testing and Development

unavailable api dependencies

Testing and development come to a halt when any one of the direct and transitive API dependencies is needed but unavailable.

Development of API Clients can be at standstill waiting for the delivery of new APIs.

External APIs charge pay-per-transaction fees even in non-production environments.

Often times API dependencies enforce rate limiting making performance testing impossible.

The Solution? API Simulations!

API Simulations imitate real APIs or APIs not built yet



API Simulations mimic the direct dependencies.


An API Simulation behaves and outputs static and dynamic data if it was "the real deal".


API Simulations are always available and every time with the right test data.

api simulations diagram

News and Announcements

API Simulator Release Candidate 1.5-RC1

October 07, 2019

We are excited to offer for download v1.5-RC1 release candidate of API Simulator, which introduces support for HTTP/2! Get your forever-free copy here...

API Simulator 1.4 is GA!

August 18, 2019

More flexibility, simplified configuration, enhanced documentation...what is not to like? Read more…

New Release - API Simulator 1.3 is out!

May 6, 2019

New release, more goodies in the toolbox. Read more…

API Simulator 1.2 Released!

January 15, 2019

API Simulator is getting better and better. Keep the feedback coming - we are listening! Read more about the release…

We invite you to learn more about API Simulator, download it, and run the examples. Why not even create API simulations to help your own testing and development?

Let us know what you think at [feedback at APISimulator.com]. Many thanks for your interest and support!

Happy API Simulating!