AssemblyAISpeech-to-text and audio intelligence APIs for building voice-powered applications.

4.5 (4)

Reviewed by Daniel Nikulshyn·Updated July 2026

Overview

AssemblyAI provides speech-to-text and audio intelligence APIs for building voice-powered applications. It offers a range of products including pre-recorded and real-time speech-to-text APIs, speech understanding API, voice agent API, and more. The platform provides industry-leading accuracy, natural language prompting, and supports 99 languages. It's used for various applications such as AI scribes, AI notetakers, agent assist, call analytics, conversation intelligence, medical transcription, and voice agents. AssemblyAI's infrastructure allows developers to build voice capabilities into any product, on any stack, and scale securely from MVP to production.

Key features

Speech-to-text in multiple languages
Speaker diarization and labeling
Sentiment, topic, and entity detection
Real-time streaming transcription
LeMUR LLM framework for audio Q&A
Automatic summarization and content safety

Pricing

Model: Freemium
Category: Speech Recognition
Rating: 4.5 / 5 (4)

Use cases

AI Transcription Services

AssemblyAI's pre-recorded speech-to-text API can be used to provide accurate and customizable transcripts in 99 languages for various industries such as media, education, and healthcare.

Real-time Voice Agents

AssemblyAI's real-time speech-to-text API and voice agent API can be used to build voice-powered applications such as customer service chatbots, virtual assistants, and voice-controlled interfaces.

Call Analytics and Conversation Intelligence

AssemblyAI's APIs can be used to analyze and understand customer calls, providing insights into customer behavior, sentiment, and preferences, which can help businesses improve their customer service and sales strategies.

Pros & Cons

Pros

High accuracy on conversational audio
Single API covers transcription and audio intelligence
Real-time streaming and batch processing
Clear developer documentation and SDKs

Cons

Per-minute pricing can scale up quickly at high volumes
Some advanced features limited to English
Requires technical integration, no end-user app

Reviews

4.5

Average from 4 ratings.

Hiroshi Tanaka

May 2, 2026

Solid for our team

We rolled this out across the team last quarter and clear developer documentation and SDKs. Speaker diarization and labeling fits neatly into how we already work, and leMUR LLM framework for audio Q&A removed a step we used to do by hand. but it has held up under daily use.

Camille Laurent

Feb 28, 2026

Years in this space

I've evaluated a lot of these over the years. What stands out here is leMUR LLM framework for audio Q&A — handled better than most — and high accuracy on conversational audio. Per-minute pricing can scale up quickly at high volumes is my one real gripe. Worth the time if this is your use case.

Daniel Schmidt

Jun 22, 2025

Use it every day

Honestly didn't expect to like it this much. Real-time streaming transcription is exactly what I needed, and clear developer documentation and SDKs. I do wish per-minute pricing can scale up quickly at high volumes, but I reach for it almost every day now and it just clicks.

Beatriz Costa

Jun 2, 2025

Years in this space

I've evaluated a lot of these over the years. What stands out here is speech-to-text in multiple languages — handled better than most — and single API covers transcription and audio intelligence. Requires technical integration, no end-user app is my one real gripe. Worth the time if this is your use case.