Soniox vs Deepgram: Speech-to-Textlatency & accuracy
Measured head-to-head, not marketing: Soniox currently leads both measured axes — median TTFS and Word Error Rate. Independent data, refreshed daily, on identical inputs. Voice quality and price are not measured.
Soniox or Deepgram — which is better?
Each provider's best model on each measured axis, last 7d. Lower is better on both:
| Axis | Soniox (best model) | Deepgram (best model) | Measured winner |
|---|---|---|---|
| Speed — median TTFS | stt-rt-v5 · 60 ms | nova-3 · 98 ms | Soniox |
| Accuracy — avg WER | stt-rt-v4 · 4.1% | nova-3 · 4.5% | Soniox |
Not measured here: price — treat those as vendor claims until measured. Full leaderboard context: the independent speech-to-text benchmark →
Every Soniox and Deepgram model, measured
All benchmarked models from both providers on the same pinned dataset, ranked fastest-first (median TTFS), last 7d:
| Model | Provider | TTFS median | TTFS p95 | WER | Samples |
|---|---|---|---|---|---|
| stt-rt-v5 | Soniox | 60 ms | 83 ms | 4.1% | 3,360 |
| stt-rt-v4 | Soniox | 60 ms | 86 ms | 4.1% | 3,360 |
| nova-3 | Deepgram | 98 ms | 154 ms | 4.5% | 3,327 |
| nova-2 | Deepgram | 98 ms | 175 ms | 5.2% | 3,330 |
Independent data, by Coval
Numbers are from the voice benchmark by Coval, a voice-AI evaluation platform that does not sell STT models — it measures every provider as a neutral third party on a pinned dataset under production-realistic conditions. Openbenchmarks mirrors the results daily with attribution; methodology and runner are open-source and reproducible.
Soniox vs Deepgram — common questions
Is Soniox faster than Deepgram for speech-to-text?
On the current 7d window, Soniox's fastest model (stt-rt-v5) has a median TTFS of 60 ms, vs 98 ms for Deepgram's fastest (nova-3) — so Soniox is faster on measured median latency. Distributions matter too: p95 is 83 ms for Soniox vs 154 ms for Deepgram.
Which is more accurate, Soniox or Deepgram?
By Word Error Rate: Soniox's best model (stt-rt-v4) averages 4.1%, vs 4.5% for Deepgram's best (nova-3) — Soniox leads on measured accuracy. Lower is better; WER is measured on identical inputs under production-realistic conditions.
Which should I pick — Soniox or Deepgram?
Soniox currently leads both measured axes (median TTFS and WER). Full per-model distributions are in the table below; price is not measured here.
Where does this data come from?
The independent voice benchmark by Coval, a voice-AI evaluation platform that does not sell STT models. Every model runs the same pinned dataset under production-realistic conditions, re-run roughly every 30 minutes; Openbenchmarks mirrors the results daily with attribution. Methodology and runner are open-source (Apache-2.0).