Follow the GitHub guide to register an app suitable for the Checks API:
- Open the Register a new app page
- Set a name and homepage URL
- Leave the callback URL empty
- Set the setup URL to https://<domain>/post-install
- Set the webhook URL to https://<domain>/webhook
- In Repository permissions, select:
  - Checks: Read and write
  - Commit statuses: Read and write
  - Contents: Read-only
  - Metadata: Read-only
  - Pull requests: Read-only
- In Subscribe to events, check:
  - Check run
  - Check suite
  - Pull request
Grab the GitHub app ID and webhook secret (optional for local development). Download a new PEM private key.

Start hottub:

hottub -gh-app-id <id> -gh-private-key <path> -gh-webhook-secret <secret>

Optionally, to improve the authorization flow, you can register an sr.ht OAuth2 client (setting the Redirection URI to https://<domain>/authorize-srht) and pass its credentials with -metasrht-client-id and -metasrht-client-secret.

License

AGPLv3, see LICENSE.