Vapi
Voice Agent PlatformsDeveloper-first voice AI infrastructure for building, testing, and scaling voice agents with any LLM.
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👍 Pros
- ✓Best-in-class developer experience
- ✓Swap any component (STT/LLM/TTS)
- ✓Free tier for prototyping
- ✓Active community and excellent docs
👎 Cons
- ✗Requires developer knowledge to use fully
- ✗Not a no-code solution
- ✗Cost can scale quickly at high volumes
Features
- ✓ Bring your own LLM
- ✓ Sub-500ms latency
- ✓ SIP & WebRTC support
- ✓ Deepgram STT
- ✓ ElevenLabs TTS
- ✓ Function calling
- ✓ Call recording
- ✓ SDKs for web, iOS, Android
- ✓ Pay-per-minute pricing
From the blog
View all →15 May 2026 · 19 reads
ElevenLabs, OpenAI TTS, and Azure: Which Voice Is Right for Your Agent?
The TTS provider you choose shapes how users perceive your voice agent. Here's a practical comparison of the three leading options for production deployments.
Read more →12 May 2026 · 11 reads
How to Evaluate a Voice AI Agent: 5 Metrics That Actually Matter
Not all voice agents are created equal. These five metrics will tell you whether an agent is ready for production — or still needs work.
Read more →9 May 2026 · 6 reads
The Voice Stack Explained: STT, LLM, and TTS
Every voice AI agent is built on a three-layer stack. Understanding each layer — and the tradeoffs between providers — is essential for building reliable, natural-sounding agents.
Read more →