Vapi
Best voice AI infrastructure for developers building phone-based AI agentsVapi is the leading voice agent infrastructure for developers — a platform you wire into your phone system to deploy AI agents that handle calls, take orders, qualify leads, and execute customer-support workflows over the phone. Where Sierra and Decagon are the all-in-one CX platforms, Vapi is the developer-facing layer: bring-your-own-LLM (OpenAI, Anthropic, custom), bring-your-own-voice (ElevenLabs, OpenAI, custom clones), bring-your-own-telephony (Twilio, Vonage, custom SIP). Vapi orchestrates the real-time pipeline: speech-to-text → LLM reasoning → text-to-speech → tool calling — at sub-500ms latency that makes conversations feel natural rather than awkward. Pay-as-you-go pricing runs ~$0.05/minute base + LLM token costs + STT/TTS costs (typically $0.10-$0.20/min total). Vapi has become the default infra for startups building voice features (AI receptionists, healthcare scheduling, lead qualification, food ordering, multi-language support lines) — companies that want voice AI as a product feature rather than a consumer-facing platform. Free tier provides $10 credit; Enterprise contracts include SOC 2, BAA for HIPAA workloads, and dedicated support.
AI Models
Key Features
- Real-time voice agent infrastructure (sub-500ms latency)
- Bring-your-own LLM (OpenAI, Anthropic, custom endpoints)
- Bring-your-own voice (ElevenLabs, OpenAI, custom clones)
- Bring-your-own telephony (Twilio, Vonage, SIP)
- Tool calling for CRM / database / API actions
- Multi-language support (50+ languages)
- Call recording + transcription + analytics
- BAA available for HIPAA workloads (Enterprise)
Integrations
Pricing
Try Vapi without commitment, all features available
Base infra + LLM tokens + STT/TTS costs (varies by config)
SOC 2, BAA available for HIPAA, dedicated infrastructure, support
Pros & Cons
Pros
- Best-in-class latency (<500ms) makes voice agents feel natural
- Bring-your-own everything (LLM, voice, telephony) — no vendor lock-in
- Pay-as-you-go pricing scales with usage, no upfront commitment
Cons
- Developer-facing — non-technical buyers should look at Sierra / Decagon
- Per-minute costs add up at scale (typical mid-volume: $5K-$30K/mo)
Who should buy this
Vapi
- Developer building voice AI as a product feature (receptionist, scheduler, qualifier)
- Startup with phone-heavy customer interaction (food, healthcare, real estate)
- Engineering team wanting BYOL LLM control over voice agent stack
- Non-technical buyers wanting an out-of-box CX platform (Sierra / Decagon better)
- Buyers without dev resources to wire BYOL pipeline
Free $10 trial. Indie dev / small deployment: $50-$500/mo. Mid-volume voice agent fleet: $5K-$30K/mo. Enterprise: custom contracts.
Verified 2026-05-03
Capabilities at a glance
| Capability | Vapi |
|---|---|
| Real-time voice pipeline (STT + LLM + TTS) | <500ms latency |
| Bring-your-own LLM | |
| Bring-your-own voice | |
| Bring-your-own telephony | |
| Tool calling in voice agents | |
| 50+ language support | |
| BAA for HIPAA | Enterprise |
| On-prem / self-hosted |
Security & compliance
| Standard / control | Vapi |
|---|---|
| SOC 2 | Type II |
| HIPAA | |
| GDPR | |
| SSO / SAML | |
| RBAC | |
| Audit logs | |
| Trains on customer data | No |
What users say
Vapi
Y Combinator-backed voice AI startups, Healthcare scheduling apps, Restaurant ordering systems