Inworld STT-1 vs Speechmatics Linden
Inworld STT-1 is ahead on time to first text and final-text delay, and Speechmatics Linden on the Pipecat Dataset and the Ocular Dataset.
Quality and speed frontier
Every model's error rate on the public clips, against how long its transcript takes to settle.
The four metrics, side by side
Word error rate on 1,000 clips from Pipecat's STT benchmark dataset.
- Inworld STT-1
- 2.72%8th
- Speechmatics Linden
- 2.46%6th
Speechmatics Linden, 0.26 points lower
Word error rate on eight licensed recordings provided by Ocular.
- Inworld STT-1
- 10.60%14th
- Speechmatics Linden
- 3.93%6th
Speechmatics Linden, 6.67 points lower
Median delay before the first words arrive, from the first audio packet.
- Inworld STT-1
- 1.06s5th
- Speechmatics Linden
- 1.19s7th
Inworld STT-1, 127ms sooner
Median delay after the speaker stops before the transcript is final.
- Inworld STT-1
- 41ms1st
- Speechmatics Linden
- 147ms6th
Inworld STT-1, 106ms sooner
Lower is better on every metric. The small figure is each model's place in the whole field.
First text and final text, at three percentiles
Both measured on the same 206 streamed Ocular Dataset turns. P90 and P95 say what a caller meets on a bad turn, which a median hides.
| Measure | Model | P50 | P90 | P95 |
|---|---|---|---|---|
| Time to first text | Inworld STT-1 | 1.06s | 1.07s | 1.07s |
| Speechmatics Linden | 1.19s | 1.56s | 2.52s | |
| Final-text delay | Inworld STT-1 | 41ms | 60ms | 65ms |
| Speechmatics Linden | 147ms | 192ms | 213ms |
Both against every other model
Open on the metric where the two sit furthest apart, with the other three a tab away.
Word error rate on eight licensed recordings provided by Ocular. Lower is better.
| # | Model | Ocular Dataset | clips | |
|---|---|---|---|---|
| 1 | Reson8 | 2.93% | 8 | |
| 2 | Cartesia Ink 2 | 3.09% | 8 | |
| 3 | Smallest Pulse | 3.46% | 8 | |
| 4 | GPT Realtime Whisper | 3.53% | 8 | |
| 5 | Google Chirp 2 | 3.80% | 8 | |
| 6 | Speechmatics Linden | 3.93% | 8 | |
| 7 | Deepgram Flux English | 4.18% | 8 | |
| 8 | Google Chirp 3 | 4.19% | 8 | |
| 9 | AssemblyAI Universal 3.5 Pro | 4.23% | 8 | |
| 10 | Deepgram Nova-3 | 4.39% | 8 | |
| 11 | Gradium | 4.45% | 8 | |
| 12 | GPT-4o Mini Transcribe | 4.45% | 8 | |
| 13 | Deepgram Flux Multilingual | 4.53% | 8 | |
| 14 | Inworld STT-1 | 10.60% | 8 | |
| 15 | GPT-4o Transcribe | 12.45% | 8 |
Counts are the clips each model returned usable text for, so they differ between models and between datasets.
Both on the other two views
Pipecat vs Ocular accuracy
Every model's error rate on the public clips, against the same model on real conversations.
Transcription response time
How soon each model returns its first words, against how soon its transcript is final.
What the numbers rest on
| Model | Pipecat clips | Ocular recordings | Turns timed | Failed |
|---|---|---|---|---|
| Inworld STT-1 | 1,000 | 8 | 206 | 0 |
| Speechmatics Linden | 998 | 8 | 194 | 12 |
A clip counts only where the model returned usable text, so counts differ between models. Word error rate is measured the same way throughout: incorrect, missing, and extra words against the reference transcript.
Frequently asked questions
Is Inworld STT-1 or Speechmatics Linden more accurate?
On the 1,000 public Pipecat clips, Inworld STT-1 scores 2.72% and Speechmatics Linden 2.46%, so Speechmatics Linden makes fewer errors by 0.26 points. On the eight licensed Ocular recordings, Inworld STT-1 scores 10.60% and Speechmatics Linden 3.93%, so Speechmatics Linden makes fewer errors by 6.67 points. Word error rate counts incorrect, missing, and extra words against the reference transcript, so lower is better.
Which is faster, Inworld STT-1 or Speechmatics Linden?
Inworld STT-1 returns first text 127ms sooner, at 1.06s against 1.19s at the median. Inworld STT-1 has the final transcript 106ms sooner, 41ms after the speaker stops against 147ms. Both are measured on the same 206 streamed turns.
How were Inworld STT-1 and Speechmatics Linden compared?
Both ran the same two datasets under the same conditions as every other model in the benchmark: 1,000 public clips from Pipecat's STT benchmark dataset and eight licensed conversation recordings from Ocular. Inworld STT-1 returned usable text for 1,000 of the public clips and Speechmatics Linden for 998. Latency uses each provider's own supported finalization contract.