Lowest latency text-to-speech API
Default pickCartesia Sonic 3 / Sonic 3.5
In Coval's independent latency benchmark, Cartesia Sonic 3.5 has the lowest time-to-first-audio in this table at about 271 ms (P50), ahead of Deepgram Aura-2 (about 293 ms), ElevenLabs Eleven v3 (about 653 ms) and OpenAI gpt-4o-mini-tts (about 775 ms). Measured medians run well above vendors' optimized marketing claims, so trust the measurement over the spec sheet. Google Gemini TTS and MiniMax are absent from the benchmark. A light estimate from a rolling window, August 2026.
DefaultCartesia Sonic 3 / Sonic 3.5snelsteCartesia Sonic 3 / Sonic 3.5
Provider offerings
| Offering | Price ($/1M chars) | ELO | TTFA | Langs | Capabilities |
|---|---|---|---|---|---|
| ElevenLabs Multilingual v2 / Eleven v3ElevenLabs | 100 | 1179 | 653 ms | 29 | streamingcloning |
| Cartesia Sonic 3 / Sonic 3.5Cartesia | 39* | 1203 | 271 ms | 42 | streamingcloning |
| Google Gemini 3.1 Flash TTSGoogle | 12* | 1212 | — | — | streaming |
| OpenAI gpt-4o-mini-ttsOpenAI | 15* | — | 775 ms | 50 | streaming |
| MiniMax Speech 2.5 TurboMiniMax | 78 | — | — | — | streamingcloning |
| Deepgram Aura-2Deepgram | 30 | — | 293 ms | 7 | streaming |
| SpeechifyAI Simba 3.2Speechify | 10* | 1240 | 398 ms | 30 | streamingcloning |
* token-/credit-priced — the headline understates real per-unit cost, so it is excluded from the cheapest ranking.
Sources
- SpeechifyAI — API pricing (TTS tiers)2026-08-20
- Artificial Analysis — Text to Speech Leaderboard (Speech Arena provider-voice, blind-vote ELO, 99 models)2026-08-20
- Coval — TTS benchmark data (TTFA P50/P95 and WER, rolling 7-day window on a pinned dataset), mirrored with methodology notes by Openbenchmarks; pulled 2026-08-20 06:30 UTC2026-08-20
- Coval — Best TTS Providers 2026 guide (successor to the 2026-05-04 benchmark post; now carries vendor-claimed latencies only, no benchmark table)2026-08-20
- ElevenLabs — API Pricing2026-08-20
- Cartesia — Pricing2026-08-20
- Google — Gemini Developer API Pricing2026-08-20
- OpenAI — API Pricing (developers.openai.com; the former openai.com/api/pricing/ URL now returns 403)2026-08-20
- MiniMax — Product Pricing (API docs)2026-06-22
- Deepgram — Pricing (Aura-2 and Flux TTS)2026-08-20
- Deepgram — TTS model docs (Aura-2 language list)2026-08-20
- MarkTechPost — Cartesia ships Sonic-3.6 (launch date, beta/API-only status)2026-08-20