> For the complete documentation index, see [llms.txt](https://doc.duaer.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.duaer.com/integrations/custom-operations.md).

# Make custom API calls for an app in Duaer

When a Duaer app node does not expose the API you need, use HTTP Request and reuse that app’s saved authentication.
## Reuse the app credential

Duaer app nodes cover common operations. If the REST path you need is not on the node, open HTTP Request, choose Predefined Credential Type for authentication, and pick the credential you already saved for that app.

Duaer attaches that credential’s auth headers or signature. You fill in the method and path. The note in node settings links here.
## Questions

### Why does Duaer still ask for HTTP Request?

Because an app node only wraps common operations. Duaer uses HTTP Request with that app’s saved credential so you can call an API the node does not expose, without pasting the secret again.