APIM Developer Portal "Try It" console shows empty request body intermittently

Hi @Andrés Camilo Chávez ,

Thanks for reaching out to Microsoft Q&A.

Could you please provide below details:

1. What exactly happens when you click Try It?
   • Do you see a 503 Service Unavailable, a CORS error, an authentication popup, or something else?
2. Can you share the full error message (and any browser console/network-trace logs)?
3. Have you recently made changes in Design mode (widgets, identity providers, delegation)?
   • If so, did you Save and Republish the portal?
4. Are you testing from the browser via the built-in CORS proxy or bypassing it?
5. Is your APIM instance in a VNet or otherwise network-isolated?

Hello @Pravallika KV , thanks for following up. Here are the answers to your questions:

1. When clicking "Try It", there is no error displayed at all. No 503, no CORS error, no authentication popup. The request body field simply appears completely empty. No example data is preloaded. On subsequent page refreshes, it may or may not populate correctly. The behavior is intermittent and non-deterministic.
2. I checked the browser DevTools (Console and Network tabs) while reproducing the issue. There are no errors in the Console (no red messages) and no failed requests in the Network tab. Everything appears to load successfully, but the body field remains blank.
3. Yes, I made recent changes in Design mode. Specifically, I disabled the Reports page and the Sign Up page. After making those changes, I did Save and Republish the portal. The issue persists after republishing. Note: the issue was already occurring before these changes were made.
4. I am testing from the browser via the built-in developer portal, using the default CORS proxy. No custom proxy or bypass configuration.
5. No, the APIM instance is publicly accessible and is not in a VNet or network-isolated in any way.

To summarize: there are no errors anywhere, no network failures, no CORS issues. The Try It console simply does not preload the example data intermittently. The same API definition sometimes shows the example body and sometimes shows an empty body on page refresh.

@Andrés Camilo Chávez , thanks for sharing the details.

Follow below steps to make Try It consistently preload the request body:

1. Inline the request schema instead of using $ref

requestBody:
  content:
    application/json:
      schema:
        type: object
        required:
          - action
          - facilityId
          - laneId
        properties:
          action:
            type: string
            enum: [Open, Close, Retry]
            example: Open
          facilityId:
            type: string
            example: facility-001
          laneId:
            type: string
            example: lane-01
          licensePlate:
            type: string
            nullable: true
            example: ABC123
      example:
        action: Open
        facilityId: facility-001
        laneId: lane-01
        licensePlate: ABC123

This avoids $ref resolution, which is the main cause of intermittent blank bodies.

2. Use examples instead of example

requestBody:
  content:
    application/json:
      schema:
        $ref: '#/components/schemas/GateCommand'
      examples:
        default:
          summary: Example gate command
          value:
            action: Open
            facilityId: facility-001
            laneId: lane-01
            licensePlate: ABC123

The portal sometimes prioritizes examples over example and is more consistent when rendering.

3. Ensure property-level example values
   • Even if you keep $ref, add example for each property inside the schema. This helps the portal merge examples correctly.
4. Force full portal refresh
   • Open an incognito window to bypass local caching.
   • Append a dummy query string to the portal URL (e.g., ?v=2) to force the SPA to reload compiled scripts.
5. If this persists

• Microsoft’s managed portal has known intermittent behavior with OpenAPI 3.0 $ref schemas.
• If you need deterministic Try It behavior for developers, the most reliable approach is either:
  • Flatten request schemas as in (1), or
  • Switch to a self-hosted portal, which doesn’t have these SPA race conditions.

@Andrés Camilo Chávez following up to see if the above information was helpful. Please let me know if you have any questions.

Hi @Pravallika KV , thanks for the suggestions. We have now tested all three and none of them resolved the intermittent behavior:

1. Inlining the request schema instead of using $ref — tested with a fully inlined version with no schema references at all. The body still appears empty intermittently.
2. Using "examples" (plural, named) instead of "example" (singular) — we had already tried this before opening the question. Same behavior.
3. Adding property-level "example" values to every field inside the schema — also tried previously. Same behavior.

We also tested combining all three approaches in a single definition (inlined schema + plural examples + property-level examples). The issue still persists.

At this point we have exhausted all the suggested workarounds. Since the issue occurs even with a fully inlined schema, no $ref, no CORS errors, no console errors, and no network failures, this appears to be a rendering or caching bug in the managed developer portal itself.