Your SaaS's Edit button opens a real editor, already logged in

Your product lets customers customize email templates. Today that's a textarea with syntax highlighting bolted on. You'd rather give them VS Code.

Each customer's templates live in their own container. Your app's Edit button opens an iframe at that container's code URL, ?folder=/templates&id=0&extension=yourco.templates, so only your template extension shows. The editor sits behind an alias on your own domain, and the container's proxy permissions carry a JWT group that reads the token from the cookie your app already sets there, granting the code program only.

The customer is logged into your product, so they're logged into the editor. No second login, no shared password, no API key in the iframe src. A customer who tampers with their own container reaches nothing but their own container.

Your login is their login. The editor just reads the cookie.