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Linden by Speechmatics

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★ 205 • Updated Sep 17, 2026, 09:07 PM

Agent STT (also marketed as Speech-to-text for AI voice agents) is a speech-to-text API from Speechmatics built specifically for real-time conversational AI voice agents.

Use Cases ▼
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Powering real-time speech recognition inside AI voice agents and phone bots

02

Adding speaker diarization so agents know which participant said what on a call

03

Live captioning and real-time subtitling for broadcasts and streams

04

Transcribing contact-center and customer-support conversations in real time

05

Building multilingual voice interfaces across 55+ languages

06

Integrating low-latency STT into agent frameworks such as LiveKit or Pipecat

07

Media monitoring and content indexing workflows that need speaker attribution

What Problem It Solves ▼

Real-time voice agents need transcription that is fast enough to feel conversational and smart enough to attribute speech to the right speaker. Traditional batch or high-latency ASR adds perceptible delay and often loses speaker context, which breaks turn-taking in live calls. Agent STT addresses this by providing a streaming speech-to-text API with approximately 350ms latency, built-in speaker identification, and broad language coverage, so developers can plug low-latency, speaker-aware transcription into voice agent frameworks instead of building or tuning ASR infrastructure themselves.

Key Features ▼
✓

Low ~350ms latency tuned for conversational voice agents

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Built-in speaker diarization/speaker identification

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Coverage of 55+ languages

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Accessible via direct API or popular agent frameworks (LiveKit, Pipecat)

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Transparent usage pricing starting at $0.30/hour with $100 free credit

Overview

Agent STT (also marketed as Speech-to-text for AI voice agents) is a speech-to-text API from Speechmatics built specifically for real-time conversational AI voice agents. It runs on a model Speechmatics describes as purpose-built for voice agents, and is designed to accurately capture both what was said and who said it within roughly 350 milliseconds of end-to-end latency. The service supports speaker diarization (speaker identification), making it possible for an agent to distinguish between speakers on a call in real time.

Pros & Cons

Pros

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Low ~350ms latency tuned for conversational voice agents

+

Built-in speaker diarization/speaker identification

+

Coverage of 55+ languages

+

Accessible via direct API or popular agent frameworks (LiveKit, Pipecat)

+

Transparent usage pricing starting at $0.30/hour with $100 free credit

Cons

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Proprietary, usage-based commercial API rather than open source

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No public GitHub repository or self-hosting option for the hosted service

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Pricing and quotas beyond the entry tier require contacting sales or checking the pricing page

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Exact model architecture and benchmarks are only partially disclosed publicly

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Latency and accuracy may vary by language, audio quality, and network conditions

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