Vapi
The Voice AI infrastructure for developers to build conversational agents in minutes.
We tested Vapi and found it to be the 'Stripe for Voice AI'. It elegantly abstracts the messy glue code required to connect transcribers, models, and synthesizers.
Why we love it
- Incredible Developer Experience (DX) with the CLI.
- Significant reduction in latency compared to DIY solutions.
- Flexible architecture allows swapping models easily.
Things to know
- Voice AI reliability relies heavily on upstream providers (e.g., Twilio quality).
- Cost can stack up (Vapi cost + LLM cost + Telephony cost).
About
Vapi is the orchestration layer for Voice AI, abstracting the complexity of Speech-to-Text, LLMs, and Text-to-Speech into a single, easy-to-use API. It handles the difficult engineering challenges of voice agents—like turn-taking, interruption handling, and latency optimization—so developers can focus on conversation logic. With a powerful CLI and SDKs, Vapi integrates seamlessly with Twilio, Vonage, and your existing tech stack (including n8n and Make) to deploy human-like voice assistants.
Key Features
- ✓Real-time turn-taking & interruption handling
- ✓Sub-second latency orchestration
- ✓Integrations with Twilio/Vonage
- ✓Supports BYO LLM (OpenAI, Groq, etc.)
- ✓Developer CLI & Webhooks
Frequently Asked Questions
Yes, Vapi is widely used with automation tools like n8n and Make. Many developers use them to handle the business logic triggered by Vapi calls.
Vapi focuses on the AI infrastructure. You can buy numbers directly through Vapi (powered by Twilio/Vonage) or integrate your existing Twilio/Vonage account.
Vapi is optimized for sub-second latency by orchestrating streaming data between STT, LLM, and TTS providers efficiently, often faster than DIY setups.
Yes, Vapi has built-in turn-taking logic that detects when a user speaks over the bot and stops the audio output immediately to listen.
Vapi typically charges a usage-based fee per minute of conversation, which is separate from the costs of the LLM, transcription, and telephony providers you choose.