Assembly AI

Unlock the power of voice data with superhuman AI models.

RecommendedAssemblyAI provides a powerful and secure Voice AI platform with leading accuracy for complex speech-to-text, understanding, and voice agent development.

AssemblyAI provides industry-leading pre-recorded and real-time speech-to-text and voice agent APIs. It offers a comprehensive platform with models, APIs, and infrastructure to build voice into any product, supporting various use cases from AI scribes to medical transcription.

Visit Assembly AI

Visit Assembly AI

Key Features:

Pre-recorded Speech-to-Text API (Universal-3 Pro, Universal-2)
Realtime Speech-to-Text API (Universal-3 Pro Streaming, Universal-Streaming)
Voice Agent API for end-to-end voice agent infrastructure
Speech Understanding API for extracting structured insights (sentiment, entities, topics)
Guardrails for compliance-grade safety (PII redaction, content moderation)

Pros

Developers building voice agents requiring high accuracy and low latency
Enterprises needing robust speech-to-text for call analytics and conversation intelligence
Healthcare providers requiring accurate medical transcription and HIPAA compliance

Cons

Pricing can become significant for high-volume usage, especially with add-on features.
Advanced features like Medical Mode and Prompting Beta have additional costs.
While supporting 99 languages, the most advanced models (Universal-3 Pro) currently support fewer languages.

Pricing

freemiumFree tier

Starting at:$0.15/hr

Free tier:Up to 185 hours of pre-recorded and 333 hours of streaming

Plans

Pre-recorded STT Universal-3 Pro: $0.21/hr
Pre-recorded STT Universal-2: $0.15/hr
Realtime STT Universal-3 Pro Streaming: $0.45/hr
Realtime STT Universal-Streaming: $0.15/hr

Categories:

Audio & Speech AI Infrastructure Code & Development

Tags:

speech-to-text real-time transcription voice agents speech understanding API AI models medical transcription call analytics conversation intelligence LLM gateway guardrails

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Quick Decision

Try if: You should try if you are building advanced voice-enabled applications, require highly accurate speech-to-text and speech understanding, or need robust voice agent infrastructure with enterprise-grade security and compliance.

Skip if: Skip if you only need basic, low-volume transcription without advanced AI features, or if your budget is extremely limited for usage-based pricing.

Not for: Individuals looking for a simple, free transcription tool for occasional use; Users who do not require API access or advanced speech understanding features

Trust Signals

Team Size
large
Funding
$50M Series C led by Accel

Compliance

SOC 2 Type 1SOC 2 Type 2GDPRPCI-DSS 4.0 Level 1

Notable Customers

ZoomSiro

Tech Details

Platforms

webapi

Integrations

LiveKitPipecatPython SDKJavaScript SDK

AI Model
Universal-3 Pro, Universal-2, Universal-3 Pro Streaming, Universal-Streaming

Open Source

Support

Channels

documentationemailsales contact

Company

Name
AssemblyAI Inc.

AssemblyAI is dedicated to advancing and democratizing Voice AI technology, building superhuman Voice AI models to unlock new applications leveraging voice data. They are a research-oriented organization focused on accurate, capable, easy-to-use, and safe AI models.

FAQ

What are the differences between AssemblyAI's Speech-to-Text models?

AssemblyAI offers Universal-3 Pro and Universal-2 for pre-recorded audio, with Universal-3 Pro being the most accurate for multilingual use. For real-time, Universal-3 Pro Streaming provides highest accuracy and Universal-Streaming is optimized for speed and cost-effectiveness, primarily for English.

Does AssemblyAI offer a free tier?

Yes, AssemblyAI offers a free tier that includes up to 185 hours of pre-recorded audio transcription and 333 hours of streaming transcription, with no credit card required to sign up.

What security and compliance standards does AssemblyAI meet?

AssemblyAI adheres to enterprise-grade security practices, including SOC 2 Type 1 and Type 2 compliance, GDPR, and PCI-DSS 4.0 Level 1 certification. They also offer encryption in transit and at rest, network security, and auditable change management procedures.

Use Cases

Developers building voice agents requiring high accuracy and low latency
Enterprises needing robust speech-to-text for call analytics and conversation intelligence
Healthcare providers requiring accurate medical transcription and HIPAA compliance