AssemblyAI

Speech-to-text API with intelligence features for developers.

Best for: Developers building transcription, audio intelligence and call analytics features into production applications.

Free plan

4.6/5Editorial score 90/100assemblyai.com

Starts at

Free ($50 credit)

Get started free

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Editorial score90/100

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The editorial note

What to know about AssemblyAI

AssemblyAI is a speech AI API platform providing accurate transcription alongside AI models for audio intelligence — including speaker diarization, sentiment analysis, topic detection, auto chapters, and PII redaction. It's used by developers building podcast tools, meeting recorders, call analytics, and voice AI applications. Known for best-in-class accuracy and a clean, well-documented API.

Is it right for you?

Who AssemblyAI suits

Choose it if

Developers building transcription, audio intelligence and call analytics features into production applications.

Look elsewhere if

Teams on tight budgets — OpenAI Whisper (open source) or Deepgram's free tier are cheaper starting points

What you get

Key features

High-accuracy speech-to-text transcription
Speaker diarization — who said what
Sentiment analysis per sentence
Auto chapters and topic segmentation
PII redaction for compliance
Content moderation for audio
LeMUR — query transcripts with AI
Real-time streaming transcription

Works with

Integrations6

Python SDKNode.js SDKGo SDKZapier MakeAWS Lambda

What it costs

Pricing

AssemblyAI pricing plans
Plan	Price	What it includes
Free	Free ($50 credit)	Get started with $50 in free credits, no credit card needed
Pay As You Go	From $0.37/hour audio	Pay per audio hour — transcription, LeMUR AI, intelligence APIs
Enterprise	Contact sales	Volume discounts, SLA, dedicated support, and on-prem options

Prices are recorded from the vendor's public pricing page and can change. Check before you buy.

The trade-off

Pros and cons

Pros

Best accuracy for transcription across diverse accents and audio quality
Speaker diarization identifies multiple speakers automatically
LeMUR — ask questions about transcribed audio with an LLM
Real-time streaming transcription for live audio
Simple, well-documented API with SDKs for Python, Node, and Go

Cons

Paid only — no free tier beyond trial credits
More expensive than AWS Transcribe for high-volume workloads
Language support is strong for English but limited for some other languages
No self-hosted option — data sent to AssemblyAI servers

Quick read

At a glance

Category: AI Tools
Pricing model: Freemium
Entry plan: Free ($50 credit)
Free plan: Available
Free trial: Not listed
Website: assemblyai.com

The verdict

Our take on AssemblyAI

The most feature-rich speech API available — intelligence features on top of transcription add real product value.

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