Sudden (since 06.10.2026) failure in eu.api.openai.com - Invalid URL (POST /v1/realtime/sessions)

API
1

I have code working to create a session with an http endpoint and taking a secret to initiate the WS connection, now last 2 days that call is failing like this.

 DEFAULT 2026-06-11T13:05:24.559256Z [Bridge] REST session creation failed (404): {                                                                                                                                   
  DEFAULT 2026-06-11T13:05:24.559274Z "error": {                                                                                                                                                                       
  DEFAULT 2026-06-11T13:05:24.559278Z "message": "Invalid URL (POST /v1/realtime/sessions)",                                                                                                                           
  DEFAULT 2026-06-11T13:05:24.559282Z "type": "invalid_request_error",                                                                                                                                                 
  DEFAULT 2026-06-11T13:05:24.559285Z "param": null,                                                                                                                                                                   
  DEFAULT 2026-06-11T13:05:24.559287Z "code": null                                                                                                                                                                     
  DEFAULT 2026-06-11T13:05:24.559291Z }                                                                                                                                                                                
  DEFAULT 2026-06-11T13:05:24.559295Z } — falling back to direct WS

Did anyone experienced this ? Anyone has any clues what is going on ? This is not intermittent issue, all the calls are failing for us (we are falling back to WS, but this is not ideal for our case).

Thanks

2

Yes, I can reproduce this issue.

The cause is that the Realtime API preview has been deprecated. Your code should probably have failed earlier, and with a more informative error message, but that does not change the main point: you will need to migrate to the GA Realtime API.

As far as I can tell, you will need to:

  • remove OpenAI-Beta: realtime=v1

  • use POST /v1/realtime/client_secrets for ephemeral browser or mobile credentials

  • update the session and event shapes for GA, including session.type, the newer audio config placement, and the newer response event names

I will ping the team to take a look at the documentation. I think this needs to be more clear, now that realtime=v1 is essentially non-functional.

Here is the migration guide:

3

Thanks Viet, i was able to fix it with EU URL yesterday. All are working now with EU http endpiont and initiate the session. It was my mistake that I thought http call worked with EU but it never worked and my collegue removed the code I added. following are the summary of the fix, if someone else can learn from it,

The issue was on our side. We were calling POST /v1/realtime/sessions (the beta endpoint) which OpenAI has retired. The fix was to migrate to the GA endpoint:

- URL: /v1/realtime/client_secrets (not /v1/realtime/sessions)

- Body: config must be wrapped in { session: { model, type: “realtime”, … } } — model and type go inside the session object

- WebSocket: remove the OpenAI-Beta: realtime=v1 header when connecting with the ephemeral key

- Response: the ephemeral token is at response.value (not response.client_secret.value)

Works on both US (api.openai.com) and EU (eu.api.openai.com) endpoints.

4

Thanks for circling back with the update @lahiru. Glad you were able to track it down and get things working again.

Also appreciate the investigation from @VeitB. The pointer about the deprecated Realtime preview API helped narrow the issue down quickly.

For anyone who finds this thread later, the root cause ended up being use of the retired beta session endpoint. The working migration was:

  • Use POST /v1/realtime/client_secrets instead of POST /v1/realtime/sessions
  • Wrap configuration as { session: { model, type: "realtime", ... } }
  • Remove the OpenAI-Beta: realtime=v1 header when connecting with the ephemeral key
  • Read the ephemeral token from response.value
  • Works with both api.openai.com and eu.api.openai.com

This is a great example of why sharing the final fix is so valuable. It will likely save others quite a bit of debugging time.

-Mark G.