Zulip uses a third party (Stripe) for billing, so working on the billing system requires a little bit of setup.

To set up the development environment to work on the billing code:

Nearly all the billing-relevant code lives in corporate/.

Upgrading Stripe API versions

Stripe makes pretty regular updates to their API. The process for upgrading our code is:

  • Go to in your Stripe account.

  • Upgrade the API version.

  • Run tools/test-backend --generate-stripe-fixtures

  • Fix any failing tests, and manually look through git diff to understand the changes.

  • If there are no material changes, commit the diff, and open a PR.

  • Ask Rishi or Tim to go to in the zulipchat Stripe account, and upgrade the API version there.

We currently aren’t set up to do version upgrades where there are breaking changes, though breaking changes should be unlikely given the parts of the product we use. The main remaining work for handling breaking version upgrades is ensuring that we set the stripe version in our API calls. has some additional information.