AssemblyAI
AssemblyAI / assemblyai.com
AI speech recognition API with real-time transcription, speaker diarization, sentiment analysis, and audio intelligence.
Pricing
Free
Free plan
Yes
Category
Transcription AI
Platforms
2
Rating
4.8 (1200)
Free plan
Yes
API access
Yes
Open source
No
Platforms
2
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What is AssemblyAI?
AssemblyAI is an AI speech recognition API used by 100,000+ developers for high-accuracy transcription, speaker diarization, sentiment analysis, PII redaction, and audio summarisation. Best in class for real-time transcription with 98%+ accuracy. AssemblyAI's Universal-2 model outperforms Whisper and Google for many use cases. Lemur is AssemblyAI's LLM for audio intelligence tasks.
How AssemblyAI works
AssemblyAI runs as asr and nlp software built around audio and text workflows. Users typically start with a prompt, upload, or connected data source, and the underlying model handles the heavy lifting before returning a result you can refine or export. It's available on web and api, with API access for teams that want to embed it into their own products.
What makes it worth shortlisting
The capabilities that matter most for teams evaluating AssemblyAI.
Universal-2 best-in-class accuracy
Practical for developers and businesses building transcription and audio intelligence features needing real-time accuracy and advanced features. without extra setup.
Real-time streaming transcription
Practical for developers and businesses building transcription and audio intelligence features needing real-time accuracy and advanced features. without extra setup.
Speaker diarization (who said what)
Practical for developers and businesses building transcription and audio intelligence features needing real-time accuracy and advanced features. without extra setup.
Sentiment and topic analysis
Practical for developers and businesses building transcription and audio intelligence features needing real-time accuracy and advanced features. without extra setup.
PII detection and redaction
Practical for developers and businesses building transcription and audio intelligence features needing real-time accuracy and advanced features. without extra setup.
100,000+ developer users
Practical for developers and businesses building transcription and audio intelligence features needing real-time accuracy and advanced features. without extra setup.
Best use cases
Who should use it
Pros
- Best-in-class real-time transcription accuracy
- Speaker diarization excellent
- Lemur LLM for audio intelligence unique
- HIPAA compliant
- PII redaction built-in
- 100,000+ developer validation
Cons
- More expensive than Whisper self-hosted
- API-only (no consumer product)
- Some advanced features on higher plans
- Less known than Google or Microsoft STT
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Is it worth the price?
Free $50 credit; pay-per-minute from $0.37/hr async; real-time from $0.42/hr; Enterprise custom
Model
Pay-as-you-go
Starting price
Free
Free trial
No
Tools like AssemblyAI
Deepgram (similar performance, competitive pricing)|Google Speech-to-Text (Google ecosystem)|Microsoft Azure Speech (Azure-native)|Rev AI (human review option)|Whisper (open-source, cheaper at scale)
AssemblyAI vs Whisper AI
A side-by-side look at the closest alternative in this category.
AssemblyAI
AssemblyAI
Whisper AI
OpenAI
Free $50 credit; pay-per-minute from $0.37/hr async; real-time from $0.42/hr; Enterprise custom
API from $0.006/minute via OpenAI API; open-source free to self-host; many third-party implementations
Developers and businesses building transcription and audio intelligence features needing real-time accuracy and advanced features.
Developers, researchers, and businesses wanting accurate speech-to-text that can be self-hosted or used via API.
HIPAA BAA available; GDPR DPA; data deletion API; SOC 2 Type II
API: data used per OpenAI policy; self-hosted: full data control; GDPR DPA for API
- Best-in-class real-time transcription accuracy
- Speaker diarization excellent
- Lemur LLM for audio intelligence unique
- HIPAA compliant
- PII redaction built-in
- 100,000+ developer validation
- Open-source with full data control option
- Near-human accuracy in most conditions
- 99 languages
- $0.006/min very affordable via API
- Foundation of most AI transcription services
- More expensive than Whisper self-hosted
- API-only (no consumer product)
- Some advanced features on higher plans
- Less known than Google or Microsoft STT
- Slower than real-time without GPU
- Speaker diarization requires extra steps
- Privacy concerns with OpenAI API usage
- No native real-time streaming
Technical & deployment info
Key facts about model providers, platforms, and team support.
Model Provider
Proprietary
Models
Universal-2, Lemur
Platforms
Web, API
Deployment
Cloud
Integrations
AWS, Azure, Google Cloud, LangChain, Zoom, Twilio, HuggingFace
Team Collaboration
Yes
Launch Year
2017
Security & privacy
Compliance signals and data-handling notes as reported by the vendor.
HIPAA BAA available; GDPR DPA; data deletion API; SOC 2 Type II
What users are saying
Verified reviews from signed-in users, stored in the backend and averaged into this tool's rating.
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Common questions about AssemblyAI
Editorial Verdict
Should you use AssemblyAI?
AssemblyAI is the best transcription API for developers building production features — Universal-2 accuracy, real-time streaming, and Lemur audio intelligence combine to make it the most capable speech API available.
Last verified July 1, 2025.