Spex is a specification language and toolkit for working with HTTP JSON APIs. For more information see the website.

• The Spex specification language strives to provide a concise way of specifying HTTP JSON APIs with Elm-style error messages;

• The Spex toolkit consists of various tools for working with specifications:

  • A verifer: that checks a specfication against a server, using fuzzing and generative testing techniques, and reports back:
    • minimised test cases that lead to non-2xx responses, or;
    • JSON response decode or type errors, as well as;
    • any non-reachable APIs.
  • A mock server: which takes a specification and creates a server which generates responses according to the specification;
  • Code generator: which takes a specification and a template and generates code, e.g. API clients, server stubs or documentation (this is not implemented yet).
  • A REPL: takes a specification and an URL and gives you a REPL which can be used to explore the server behind the URL, which tab completion generating random payload data for the different possible API calls (not implemented yet);
  • A debugger: which takes a test case and lets you step forwards and backwards one API call at the time and gives you a REPL to explore the system under test in between the steps (not implemented yet);
  • A import and exporter: which allows for conversion to and from other specification formats, e.g. OpenAPI (not implemented yet).

For a more elaborate explaination of the motivation behind Spex, see the following link.

See INSTALL.md for installation instructions.

The easiest way to get started is to follow the installation instructions above to obtain the spex and spex-demo-petstore binaries, and then clone this repo to get access to the examples:

git clone https://github.com/spex-lang/spex.git
cd spex
spex-demo-petstore & # Start the demo HTTP API server in the background.
spex verify example/petstore-modal-faults.spex --tests 2000
kill $! # Stop the demo server ($! contains the pid of the last child process).

(You can also open the demo server in a separate terminal and avoid starting it in the background and killing it.)

For a longer introduction, including what's happening behind the scenes when you run e.g. spex verify, see the tutorial.

If you got any questions or what to discuss what else we can do with specification, come join one of our chats:

Please make sure you follow the code of conduct when interacting with others.

Spex is at an early stage of development and is open to various forms of contribution, see the CONTRIBUTING.md file for details.

BSD-2-Clause (see the file LICENSE).