You can use a domain from your Express web server for Rebrandly branded short links by setting it up as an alias domain and installing the rebrandly-express middleware package.
While this approach works, we recommend using a dedicated domain for your branded links whenever possible. A dedicated domain requires no server configuration, has fewer points of failure, and removes the dependency on your website staying correctly configured. See How do I get a branded domain?
For full setup instructions, including prerequisites, step-by-step configuration, and code examples, see the developer documentation:
The rebrandly-express package (v0.0.6) has not been updated in several years. It is confirmed working on Express 4. Compatibility with Express 5 is unconfirmed — test in a staging environment before deploying to production.