# Accessing external userId from generate-signed-access-url inside a workflow — which variable?

**URL:** <https://community.mindstudio.ai/t/accessing-external-userid-from-generate-signed-access-url-inside-a-workflow-which-variable/2070>\
**Category:** Community Discussion\
**Created:** [May 15, 2026, 9:02pm UTC](https://community.mindstudio.ai/t/accessing-external-userid-from-generate-signed-access-url-inside-a-workflow-which-variable/2070 "2026-05-15T21:02:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Manuel](https://avatars.discourse-cdn.com/v4/letter/m/67e7ee/32.png) [@Manuel](https://community.mindstudio.ai/u/Manuel)\
**Post date:** [May 15, 2026, 9:02pm UTC](https://community.mindstudio.ai/t/accessing-external-userid-from-generate-signed-access-url-inside-a-workflow-which-variable/2070/1 "2026-05-15T21:02:37Z")

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Hi folks,

I am embedding a MindStudio agent via signed access URLs into our React app, and I need the workflow’s HTTP Request block to fetch user-specific data from our own backend.

Our backend calls `generate-signed-access-url` passing our internal `userId` (e.g. `tb-user-abc123`). The signed URL gets embedded in an iframe. When the workflow starts, an HTTP Request block calls our backend endpoint to fetch the session data for that specific user. The backend needs to know which user is asking so it can look up the right data in our database.

I confirmed separately that when I call `generate-signed-access-url` with `userId: "tendbe-test-abc123"`, the API correctly returns that same value in the response body, so MindStudio is storing it against the managed user record. It just does not appear to surface it to the workflow runtime through any variable syntax I have found.

So the question is , when I call `generate-signed-access-url` passing an external `userId`, is there a workflow variable that exposes that exact value at runtime so an HTTP Request block can pass it to an external API? Or is there a recommended pattern for fetching user-specific external data inside a signed-URL-triggered workflow?

thanks!

Manu

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**Author:** ![Alex\_MindStudio](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.mindstudio.ai/alex_mindstudio/32/27_2.png) [@Alex\_MindStudio](https://community.mindstudio.ai/u/Alex_MindStudio)\
**Post date:** [May 18, 2026, 5:36pm UTC](https://community.mindstudio.ai/t/accessing-external-userid-from-generate-signed-access-url-inside-a-workflow-which-variable/2070/2 "2026-05-18T17:36:27Z")

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Hi @Manuel,

Thanks for the post!

There’s currently no workflow variable that exposes the external userId you pass to generate-signed-access-url. The recommended workaround is to append it as a URL query parameter before loading the signed URL:

1. Add Launch Variables in the Start block (e.g., userID)
2. Call the API and get the signed URL back
3. Append your variables to it before loading it: returnedUrl`&userID=YourUserID`
4. Use that final URL as your iframe src

The query parameters will then be accessible inside the workflow as variables.