The CodeCrafters creators program is invite-only. Interested in building CodeCrafters challenges? Write to us at

Once you’ve pre-launched your challenge, you’re ready to start building out the stage instructions and test cases.

It’s upto you whether you want to build test cases first or stage instructions first. We recommend building both in parallel, one stage at a time. This allows you to think about how a learner will progress through your challenge, and what they’ll need at each stage.

Test Cases

For each stage defined in your course-definition.yml file, you’ll need a corresponding test case. These are defined in your tester repository. Here are some examples from our other challenges:

We recommend testing your test cases against a “reference” implementation. For example, in the Git challenge we test git-tester by running it against the official git command.

Stage Instructions

Stage instructions are present in the course-definition.yml file (under the description_md key). Here are some examples from our other challenges:

Note: we’re still building the external course authoring feature, so updates to your tester program might not be visible on immediately. Updates to the stage instructions should be visible immediately once they’re “applied” from the admin area. Let Paul know if you run into any issues.