When I trigger this API for a websocket call:

curl --location 'https://api.vapi.ai/call' \
--header 'authorization: Bearer 90947ae3-94ca-46d2-a4a5-b7665912f759' \
--header 'content-type: application/json' \
--header 'Cookie: _cfuvid=s3GI9uVVCtYM7jKZAx106nOLCnP2xvmj5AHoWQdyJBI-1746269265225-0.0.1.1-604800000' \
--data '{
    "assistantId": "d539f5aa-59bc-4a2f-9fbd-b0a349010c2d",
    "transport": {
      "provider": "vapi.websocket"
    }
  }'

This is the response that I get:

{
  "transport": {
    "provider": "vapi.websocket",
    "websocketCallUrl": "wss://phone-call-websocket.aws-us-west-2-backend-production1.vapi.ai/0f80953a-2a98-4150-9d7a-1cd093e318c1/transport"
  },
  "assistantId": "d539f5aa-59bc-4a2f-9fbd-b0a349010c2d",
  "id": "0f80953a-2a98-4150-9d7a-1cd093e318c1",
  "orgId": "c7eeddf1-2236-4c47-9505-cf0c1dfa66b4",
  "createdAt": "2025-05-03T10:47:45.085Z",
  "updatedAt": "2025-05-03T10:47:45.085Z",
  "type": "vapi.websocketCall",
  "status": "queued"
}

But when connecting the websocketCallUrl, it returns 500 internal server error (see the attached screenshot), can you please help me with this? https://cdn.discordapp.com/attachments/1368180917872492606/1368180918287863891/Screenshot_2025-05-03_at_4.19.07_PM.png?ex=68174946&is=6815f7c6&hm=cae700de262cfaa8d9491a51ae4e9ade54fc3141e623f2245ccf48bf14706927&

Since you're getting a 500 Internal Server Error (server-side issue), try these steps: 1. Retry the request - Sometimes these errors are temporary 2. Check URL validity - Ensure the websocket URL hasn't expired (they're often valid for only a short time) 3. Establish connections in order - First connect to

/transport

then to

/listen

as the listen endpoint expects the transport connection to be established first If the issue persists, contact Vapi support with your error details and timestamp. Sources: - [Discord discussion about websocket transport issues](https://discord.com/channels/1211482211119796234/1341810370700120064) - [Discord discussion about 500 errors](https://discord.com/channels/1211482211119796234/1328923059905630238) - [Discord discussion about websocket URL validity](https://discord.com/channels/1211482211119796234/1329235631855108128)

Follow this guide, https://docs.vapi.ai/calls/websocket-transport

I did try that @Sahil! Using the curl (Create a websocket call) from the docs, I received this error:

{
  "message": [
    "assistant.property assistantId should not exist",
    "transport.audioFormat.an unknown value was passed to the validate function"
  ],
  "error": "Bad Request",
  "statusCode": 400
}

Then I removed the audioFormat object, and replaced

"assistant": { "assistantId": "d539f5aa-59bc-4a2f-9fbd-b0a349010c2d" },

with

"assistantId": "d539f5aa-59bc-4a2f-9fbd-b0a349010c2d"

This worked fine. But when I tried to connect to the wss endpoint, it returned "Internal Server Error" (See the screenshot attached in the previous message) https://cdn.discordapp.com/attachments/1368180917872492606/1368289992857751613/Screenshot_2025-05-03_at_11.41.32_PM.png?ex=6817aedb&is=68165d5b&hm=69bac4c5ab8523f25112302f37dede20e5d0f50849fc8356488771b714b38c1c& https://cdn.discordapp.com/attachments/1368180917872492606/1368289993226715266/Screenshot_2025-05-03_at_11.43.40_PM.png?ex=6817aedb&is=68165d5b&hm=10802100cab43829748fa9b50f1da169fb58a55ad356ac2fd8fd0a2d324f6350&

Looks like a bug cause ideally we need to provide the audioFormat otherwise it will not work.

Yes @Sahil, because as per the docs, it looks straightforward. Can you get it checked once and let me know the next steps?

Sure, give me some time. Today is sunday so most of the folks are offline.

No problem, Thanks

They are on PST Timezone, but we will working on it.

Thanks for the info @Sahil

Any update ?

Hey @bauman you can track it over here

It's been more than 10 days, any updates on this? @Sahil @Shubham Bajaj

Hey Yash, we’ve got quite a bit going on right now, and honestly, we’re not seeing many complaints about this. So, it’s going to take a little longer.