Vapi
Developer platform for building voice AI agents that make and take phone calls.
Visit Vapi Pay per minute (platform fee from $0.05/min plus provider costs); free trial credit
What is Vapi?
Vapi is an API-first platform for voice agents: pick a speech-to-text, LLM, and text-to-speech provider, define the agent, and deploy it to phone numbers or web calls, with tool calling, interruptions, and latency tuning handled for you.
Key features
- Mix and match STT, LLM, and TTS providers
- Inbound and outbound phone calls plus web voice
- Function calling for bookings, lookups, and CRM actions
- Sub-second latency tuning and interruption handling
- Call recordings, transcripts, and analytics
Pros
- Most flexible provider choice of the voice-agent platforms
- Developer-grade API and SDKs
- Scales from a hobby project to a call centre
Cons
- Per-minute costs stack across platform plus three providers
- Requires real engineering — not a no-code builder
- Voice quality and latency depend on the providers you pick
Best for
Developers building phone or in-app voice assistantsStartups automating inbound callsTeams that want control over every layer of the stack
Read more
Related comparisons
Alternatives to Vapi
Retell AI
Build, test, and deploy phone voice agents with a visual flow builder.
PaidPay as you go from about $0.07/min; free trial minutes
Released December 2023
Bland AI
Enterprise phone agents that sound human, with self-hosted infrastructure.
PaidFrom about $0.09/min; enterprise volume pricing
Released August 2023
ElevenLabs
4.9
The AI voice generator with the most realistic output.
FreemiumFree 10k chars/mo, Creator $22/mo
Released January 2023