The API Simulatorâ„¢ downloads contain the full set of features for each edition. There are no limits on hosts/servers, environments, number of simulations, internal users, concurrent network connections, CPUs, CPU cores, virtual vs. physical, cloud or on premise, etc.

Fully functional and free forever – download your copy below.



Standalone HTTP API Simulator v1.5-RC1 (release candidate)

Choose and download the file for your platform (Mac users – choose the ZIP):

ZIP : sha256 = 84ee308d57f8fc9d9340f26d1e991c940de14d9721d39489cdbfd9926da14148

TAR : sha256 = 273ea4f8be37b3826f8dba663b820b503a657f324c02932953ba136f9db56d05

This release candidate introduces support for HTTP/2.

HTTP/2 implementation detals:

  • Auto-detection of the HTTP protocol – HTTP/1.x or HTTP/2. No additional startup arguments required!
  • Support for HTTP/1.x and HTTP/2 requests on the same port number.
  • Support for HTTP and HTTPS on the same port number for HTTP/1.x and HTTP/2 requests.
  • Support for cleartext (“http” URIs) upgrade from HTTP/1.1 to HTTP/2.
  • Support for starting HTTP/2 for “https” URIs with the TLS Application-Layer Protocol Negotiation (ALPN) extension.
  • Support for starting HTTP/2 with “prior knowledge”.


  • HTTP/2 settings like maximum frame size and others aren’t currently configurable.
  • The size in the Access Log is always 0 (zero) for HTTP/2 responses.

We would love to hear your feedback – contact us via email at [feedback at]. Many thanks for your interest and support!


Standalone HTTP API Simulator v1.4.1 (stable)

Choose and download the file for your platform (Mac users – choose the ZIP):

ZIP : sha256 = 7cf557d4fc25409d47b1855dbafee3be6a9744cecc4fe17c080b92049d087dd1

TAR : sha256 = ac6ad1181769fe7cb256f52f197bcd8fec179b865f4797163a789e78b1aa6a93


Embedded HTTP API Simulator v1.4.1 (stable)

JAR : sha256 = b2d7c4958287441342c61eb7747a3413e26dbb5ca3fcbf57e92249415e88a3c3


Click here for the documentation.


Happy API Simulating!