AssemblyAI Documentation

Quickstart	Description
Pre-recorded Speech-to-Text API	Transcribes recorded audio and video asynchronously across 99 languages, with support on speaker diarization, PII redaction, and more features. Built for teams processing recorded calls, podcasts, or meetings at scale.
Streaming Speech-to-Text API	Handles live audio over WebSocket with ~150ms p50 latency, powering voice agents, live captions, and real-time agent-assist tools in contact centers.
Synchronous Speech-to-Text API	Transcribes short audio clips (up to 120 seconds) in a single request-response call — no polling or webhooks needed. It’s suited for quick, low-latency transcription use cases with need for limited transcription features.
Voice Agent API	A fully managed speech-to-speech pipeline — one connection handles STT, LLM reasoning, and TTS together at roughly one second end-to-end latency, for teams that want AssemblyAI to own the whole voice-agent stack rather than assembling it themselves.
Speech Understanding API	Layers speech analysis on top of transcripts — summarization, sentiment, topic detection, and more over audio — for extracting structured insight.
Guardrails API	Provides safety, privacy, and compliance controls — PII handling, content moderation, and related safeguards — for teams that need to govern what audio data flows through their pipeline.
LLM Gateway API	Gives unified access to frontier language models through the same API, so teams can apply reasoning models to their transcription without a separate integration.

Quickstart

Description

Transcribes recorded audio and video asynchronously across 99 languages, with support on speaker diarization, PII redaction, and more features. Built for teams processing recorded calls, podcasts, or meetings at scale.

Streaming Speech-to-Text API

Handles live audio over WebSocket with ~150ms p50 latency, powering voice agents, live captions, and real-time agent-assist tools in contact centers.

Synchronous Speech-to-Text API

Transcribes short audio clips (up to 120 seconds) in a single request-response call — no polling or webhooks needed. It’s suited for quick, low-latency transcription use cases with need for limited transcription features.

Voice Agent API

A fully managed speech-to-speech pipeline — one connection handles STT, LLM reasoning, and TTS together at roughly one second end-to-end latency, for teams that want AssemblyAI to own the whole voice-agent stack rather than assembling it themselves.

Speech Understanding API

Layers speech analysis on top of transcripts — summarization, sentiment, topic detection, and more over audio — for extracting structured insight.

Guardrails API

Provides safety, privacy, and compliance controls — PII handling, content moderation, and related safeguards — for teams that need to govern what audio data flows through their pipeline.

LLM Gateway API

Gives unified access to frontier language models through the same API, so teams can apply reasoning models to their transcription without a separate integration.

Choose how you build

API reference

Build directly against the raw HTTP and WebSocket API for full control over requests and responses.

SDK

Use the Python or TypeScript SDK to integrate transcription, streaming, and voice agents directly into your own codebase.

Build with an AI coding agent

Wire AssemblyAI into Claude Code, Cursor, or any MCP-compatible agent via the AssemblyAI MCP Server and skill.

Integrations

Drop AssemblyAI into existing voice-agent frameworks and platforms — LiveKit, Pipecat, Twilio, Langflow, and others.

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Administration

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AssemblyAI Documentation

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API reference

SDK

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API reference

SDK

Build with an AI coding agent

Integrations

Choose how you build