Testing Vapi

You built your assistant on Vapi. Testzilla is the testing layer you plug in beside it — vendor-neutral but vendor-interactive. It drives your real Vapi assistant the way your users do: it dials in to your assistant for a real inbound phone call, or connects the Vapi browser SDK directly to your assistant over WebRTC. No migration, no rebuild. (Outbound phone — your assistant calling Testzilla — is coming soon.)

What you can test

Surface	Connection type	What it exercises
Phone line	Phone	Real inbound call through Vapi telephony (Testzilla dials your assistant): ASR, LLM, TTS, routing. Outbound coming soon.
Browser voice	Web Voice	A real WebRTC session with the Vapi browser SDK connected to your assistant

Note

Vapi covers the voice surfaces — phone and browser WebRTC. For a fast, cheap text-only regression gate on agent logic, that path (LLM Chat) currently runs on Retell.

Why teams test Vapi with Testzilla

Bring your assistant as-is

Point Testzilla at your existing Vapi assistant. Your Vapi configuration is untouched.

Real calls, real WebRTC

Testzilla places actual phone calls and runs real browser voice sessions — the exact path your users take.

Catch regressions early

Run the same scenarios on every change so a prompt or voice-config tweak that breaks a flow shows up in a test, not a support ticket.

Track quality over time

Scores roll up across runs, so you can see a Vapi assistant’s pass rate trend instead of guessing.

Get started

1. Have your Vapi credentials and assistant details ready.
2. Follow the phone or web voice guide. On the Phone channel, switch the provider from the Retell default to Vapi.
3. To compare the same suite across several channels, run a suite.

Tip

Automate Vapi tests from CI via the API or from an AI agent via MCP.

Related providers

Testing Retell All four connection types for Retell agents.

Testing ElevenLabs Web Voice for ElevenLabs Conversational AI.