---
id: "2026-09-17-speechmatics-agent-stt-linden"
url: "https://postcutoff.com/e/2026-09-17-speechmatics-agent-stt-linden/"
as_of: "2026-11-13T13:49:00+01:00"
date: "2026-09-17"
date_precision: day
category: product
importance: 2
confidence: high
status: [Confirmed]
sources: 5
editor: human editor
human_review: null
version: "2026-10-04"
---

As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/e/2026-09-17-speechmatics-agent-stt-linden/

# Speechmatics launches Agent STT, powered by its Linden model, for voice agents

On 2026-09-17 Speechmatics launched Agent STT, a speech-to-text API built for production voice agents and powered by its new Linden 1 model. It returns speaker-attributed segments with turn events rather than a word stream, and Speechmatics reports a 1.05% semantic error rate and 369 ms median finalization on Pipecat's 23-model streaming STT benchmark. Launch price is $0.30/hour.

## Key facts
- Model: linden-1, served on a new /v2/agent endpoint; 55+ languages; segments finalized in under 350 ms
- Pipecat STT benchmark (vendor-cited): 1.05% pooled semantic error rate, 369 ms median finalization, on the speed/accuracy Pareto frontier of 23 streaming models
- Pricing: $0.30/hour at launch, $0.16/hour with volume discount
- Custom vocabulary up to 1,000 terms, live diarization and speaker ID; available via API, Pipecat and LiveKit
- Follows Melia 1 (2026-06-17), Speechmatics' code-switching multilingual batch model across 55+ languages

## What happened

Speechmatics, the UK speech-recognition company, shipped a separate STT product for LLM voice agents. Its Linden 1 model is tuned for the errors that break calls:
a changed digit in an account number, a missed negation, a dropped one-word confirmation. Output comes as speaker-attributed segments with turn messages, ready to hand to an LLM.

## Why it matters

Voice-agent STT is now a separate product category (Deepgram Flux, AssemblyAI Universal-3.x Pro Realtime, Cartesia Ink-2, Speechmatics Agent STT). Vendors compete on turn detection, semantic errors and finalization latency, not only average WER.
The benchmark numbers are Speechmatics' reading of Pipecat's public benchmark, not an independent audit.

## Your AI and this story

- GPT-6 Astra (training cutoff April 2026): 140 days after its cutoff
- Claude Opus 5.5 (training cutoff June 2026): 79 days after its cutoff
- Gemini 4 Hydrogen (training cutoff March 2026): 170 days after its cutoff
- Grok 4.7 (training cutoff May 2026): 109 days after its cutoff

## Sources

1. [Speechmatics press release (GlobeNewswire): Agent STT](https://www.globenewswire.com/news-release/2026/09/17/3364138/0/en/speechmatics-launches-agent-stt-for-the-speech-errors-that-derail-voice-agents.html) (globenewswire.com, official)
2. [Speechmatics Agent STT product page](https://www.speechmatics.com/voice-agents) (speechmatics.com, official)
3. [Speechmatics docs: models (Linden 1, Melia 1)](https://docs.speechmatics.com/speech-to-text/models) (docs.speechmatics.com, docs)
4. [Speechmatics: Introducing Melia](https://www.speechmatics.com/company/articles-and-news/introducing-melia-multilingual-speech-to-text-model) (speechmatics.com, official)
5. [HackerNoon: Pipecat benchmarked 23 real-time STT models](https://hackernoon.com/pipecat-benchmarked-23-real-time-stt-models-for-voice-agents-there-isnt-one-winner) (hackernoon.com, press)

## Changes

- 2026-09-29 (filed): Created

## Related

- 2026-08-12: [Deepgram launches Flux TTS and passes $100M ARR](https://postcutoff.com/e/2026-08-12-deepgram-flux-tts/index.md)
- Models: [Speechmatics Linden 1 (Agent STT)](https://postcutoff.com/m/speechmatics-linden-1/) (`speechmatics-linden-1`)