ello VAPI Team,

I am having a persistent issue trying to initiate a call from my local development environment using the @vapi-ai/web SDK.

The Problem: When I call the vapi.start() method, the request to https://api.vapi.ai/call/web fails with a 400 Bad Request, which the browser then reports as a CORS error.

My Setup:

Framework: React with Vite

SDK Version: Latest @vapi-ai/web installed via NPM

Initialization: new Vapi({ publicKey: 'bcb50c79-d0bf-41f7-8a64-256c7cf6a2db' })

Start Call: I have tried all three methods: vapi.start({ assistantId: '...' }), vapi.start('...'), and vapi.start(fullAssistantObject). All result in the same 400 Bad Request.

CORS Configuration: My Public API Key in the VAPI dashboard is configured with "Origins: All domains allowed".

What I've Tried:

Verified the Assistant ID is correct and works in the VAPI playground.

Ensured the Public Key is correct.

Cleared all server and browser caches repeatedly.

Confirmed there are no network blocks or VPNs.

Despite the "All domains allowed" setting, the browser consistently blocks the request. The underlying 400 Bad Request suggests the request is malformed, but I am following the documented methods.

Could you please advise why the server would be rejecting these requests with a 400 error from a standard Vite development environment? Is there an undocumented requirement for the .start() method's payload?

Thank you for your help.