Compare realtime APIs
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| Cartesia Sonic Cartesia | Gradium TTS Gradium | Rime TTS (Coda, Mist v3) Rime Labs | |
|---|---|---|---|
| Category | Text-to-speech | Text-to-speech | Text-to-speech |
| Status | GA | Beta | GA |
| Est. per minute | $0.034 - 0.059 | $0.032 - 0.052 | $0.027 - 0.045 |
| How that was worked out | 900 chars/min at 1 credit/char. Low = Scale plan effective ~$37.4/1M; high = Pro overage $65/1M. | 900 chars/min; L plan ~$35.9/1M vs XS ~$57.8/1M | 900 chars/min; Mist v3 vs Coda at Starter rates |
| Pricing model | subscription | subscription | per-character |
| Free tier | 20K credits/month, overages blocked; commercial use not listed for Free (Pro and up: yes). | 45K credits/month, non-commercial | Page conflicts: '~800 minutes free (about 800k characters)' vs FAQ '3,000 free minutes' |
| Connects by | WebSocket, HTTP chunked, SSE | WebSocket | WebSocket, HTTP chunked |
| Audio in | Text (no SSML required; break tags supported) | Text | Text (custom pronunciation via spell() and dictionaries) |
| Audio out | Raw container; pcm_f32le, pcm_s16le, pcm_mulaw, pcm_alaw at 8000/16000/22050/24000/44100/48000 Hz on the WebSocket | Not verified | pcm, mp3, mulaw (audioFormat); sample rates per model reference |
| Languages | 44 (Sonic 3.6) | English, French, German, Spanish, Portuguese (AWS Marketplace listing) | Coda: 8; Mist v3: 4 |
| Latency (vendor claim) | Third-party sources quote Cartesia's claims of ~90 ms time-to-first-audio for Sonic 3 and ~40 ms for Sonic Turbo; Sonic 3.6 described as sub-90 ms. Independent benchmarks reported 128-166 ms medians including network for Sonic 3/3.5. | Vendor: ~200 ms first audio; vendor-reported Coval P50 TTFA 158 ms. | Vendor: sub-200 ms end-to-end via cloud API; Mist v3 typical TTFB well below 100 ms; Coda sub-100 ms model latency on GPU engine (self-hosted) plus 25-50 ms network from most of the US. |
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| Compliance | Not verified in this pass (enterprise custom terms available). | Not verified. | Enterprise: BAA and SOC 2 reports; optional request-data retention controls (disabled by default). |
| Self-hostable | No | No | Yes |
| Last checked | 2026-10-10 | 2026-10-10 | 2026-10-10 |
| Key numbers and features | |||
| $/1M chars | $50 | $57.8 | $50 |
| Free tier | Yes | Yes | Yes |
| Free credit $ | - | - | - |
| Free tier commercial | No | No | - |
| Voices | - | - | - |
| Cloning | Yes | - | - |
| Instant clone | Yes | - | - |
| Text stream in | Yes | Yes | Yes |
| Timestamps | Yes | - | Yes |
| Emotion | Yes | - | - |
| SSML | - | - | - |
| 8 kHz phone | Yes | - | Yes |
| Latency ms | 90 | 200 | 200 |
| Languages | 44 | 5 | 8 |
| Max session min | - | - | - |
| Concurrency | 3 | 5 | 20 |
| WebRTC | No | No | No |
| WebSocket | Yes | Yes | Yes |
| gRPC | No | No | No |
| HIPAA | - | - | Yes |
| SOC 2 | - | - | Yes |
| EU data | - | - | - |
| Self-host | No | No | Yes |
| Open weights | No | No | No |
| High warnings | 0 | 1 | 1 |