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

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.