# Benchmarking Real-Time Voice AI APIs: Cartesia vs Deepgram vs ElevenLabs (2026)

> Source: <https://dev.to/mrzitoun/benchmarking-real-time-voice-ai-apis-cartesia-vs-deepgram-vs-elevenlabs-2026-2n8c>
> Published: 2026-09-03 19:32:42+00:00

When building conversational agents or real-time voice applications, latency is the defining metric. If Time-to-First-Byte (TTFB) exceeds 200ms, natural turn-taking breaks down and conversational interruption becomes clunky.

We recently recorded and aggregated median latency and pricing metrics across the primary streaming Text-to-Speech APIs using WebSocket connections (US-East endpoints, median across 1,000 requests).

| Provider | Model | TTFB Latency | Pricing / 1M Chars | Real-Time Suitability |
|---|---|---|---|---|
Cartesia |
Sonic-3 | 85ms | $20.00 | Excellent (Fastest turn-taking) |
Deepgram |
Aura-2 | 115ms | $15.00 | Very Good (Lowest bulk cost) |
ElevenLabs |
Flash v2.5 | 135ms | $25.00 | Best Voice Realism |
PlayHT |
PlayDialog | 180ms | $25.00 | Good |
OpenAI |
TTS-1 | 240ms | $15.00 | Slower (Chunked HTTP) |

The full benchmark dataset, methodology, and continuous updates are documented at [VoiceAIBench](https://voiceaibench.com).

Raw data and contributions are also maintained on GitHub: [awesome-voice-ai-latency](https://github.com/mrzitoun/awesome-voice-ai-latency/).