What you were expecting:
Docs clearly say to register your express server handler at /graphql. Then GraphiQL should work once the server starts.

What happened instead:
GraphiQL loads index.html, but fails to fetch schema or make requests. All requests 404 as they are directed at the wrong handler path.

Steps to reproduce:

1. Register express server handler using /graphql as path like docs say.
2. Build/start express server.
3. Open GraphiQL in web browser
4. Notice that schema cannot be fetched and queries/mutations fail.

Related code:
See:

• here --> Should be \graphql or configurable to match a custom path
• here --> Should be removed

More info
GraphiQL is making requests to the wrong express handler due to a misconfiguration. If I register the handler at the base express path /, then it works fine.

Environment
Node