AssemblyAI
The best way to build Voice AI apps
Founded
N/A
Starting Price
$0
Category
Developer Tools
Last updated February 7, 2026
About AssemblyAI
AssemblyAI provides production-ready speech-to-text and speech understanding AI models for developers building voice AI products. The platform delivers industry-leading accuracy with the lowest Word Error Rate, processing 600M+ monthly inference calls for thousands of companies from startups to Fortune 500 organizations.
Pros & Cons
Pros
- Industry-leading 94.1% English accuracy outperforming Amazon, Microsoft, and OpenAI
- 21% better alphanumeric recognition for phone numbers, product codes, and IDs
- Exceptional developer experience with clear documentation and responsive support
- Cost-effective pay-as-you-go model with no upfront commitments
- Companies ship AI features in weeks with measurable ROI
Key Features
Universal-3 Pro Speech Model
Promptable speech language model with 6-language support using advanced prompt-based architecture for domain-specific customization
Real-Time Streaming Transcription
WebSocket-based real-time transcription with sub-300ms latency, unlimited concurrency, and end-of-turn detection
99+ Language Support
Multilingual speech-to-text with 94% English accuracy and automatic language detection across all major world languages
Speaker Diarization
Accurately identifies and distinguishes between multiple speakers including overlapping speech
Audio Intelligence Suite
Entity detection, topic detection, sentiment analysis, key phrases, auto chapters, and custom formatting
Voice AI Guardrails
Built-in content moderation, PII redaction, audio redaction, and profanity filtering for compliant applications
Natural Language Prompting
Guide transcription behavior using plain English prompts to improve accuracy for specific domains without retraining
Pricing
Free
$0
- $50 in API credits
- Up to 185 hours pre-recorded transcription
- Up to 333 hours streaming
- Community support
Pay as You Go
$0.15/hour
Best For
Meeting Intelligence & Call Analytics
Transcribe sales calls and meetings to generate summaries, extract action items, and analyze sentiment for coaching insights
Healthcare Documentation
Convert doctor-patient conversations into structured medical documentation with HIPAA-compliant PII redaction
Customer Intelligence Platforms
Process customer feedback from interviews and support calls to extract insights at scale with near-human accuracy
Media Accessibility & Live Captioning
Generate real-time captions for live broadcasts and events with sub-300ms latency meeting accessibility requirements