Assembly AI
by AssemblyAI
Voice AI infrastructure for builders
Score
Score
Our verdict
Industry-leading Speech AI platform for transcribing speech, building voice agents, and extracting insights from audio.
Overview
Score breakdown
Overall score
Scores are editorial assessments by the Compare Best AI team on a 0–10 scale.
Expert review
CompareBestAI
Compare Best AI · Editorial Team
AssemblyAI provides production-ready Speech AI APIs including pre-recorded, realtime, and sync Speech-to-Text, Speech Understanding, Guardrails, LLM Gateway, and Voice Agent APIs. Pay-as-you-go pricing covers STT models such as Universal-3.5 Pro and Universal-2, streaming transcription, add-on features like speaker diarization and sentiment analysis, plus token-based LLM Gateway models. Sign up free; volume and enterprise plans available via sales.
How we tested
Days tested
7 days
Tasks evaluated
- ·Core Developer workflow test
- ·Pricing and plan evaluation
- ·Feature completeness review
- ·Ease of use and onboarding assessment
Method
Compared against Deepgram and Google Cloud Speech-to-Text using identical inputs
Reviewer
CompareBestAI
Plans & pricing
Universal-2 Pre-recorded STT
Cost-efficient multilingual transcription
- 99-language support
- Pre-recorded speech-to-text
Universal-3.5 Pro Pre-recorded STT
Highest-accuracy asynchronous transcription
- Native code-switching
- Keyterms prompting
- Word-level timestamps
Streaming STT
Live transcription
- Streaming WebSocket transcription
- Session-duration billing
Universal-3.5 Pro Realtime
High-accuracy real-time speech recognition
- Realtime Universal-3.5 Pro
Voice Agent API
All-inclusive voice-agent workloads
- Speech-to-text
- LLM
- Text-to-speech
Pricing may vary by region. Always verify on the vendor's website.
Feature comparison
| Feature | Assembly AI | Deepgram | Google Cloud Speech-to-Text |
|---|---|---|---|
| Core | |||
| High-accuracy speech-to-text transcription | |||
| Speaker diarization | |||
| Output | |||
| Sentiment analysis | |||
| Summarization | |||
| Pricing | |||
| Free plan available | |||
| Dev | |||
| Public API | |||
| Integrations | |||
Is it right for you?
Good fit for
Voice agents and AI notetakers
Voice agents and AI notetakers
Call analytics and medical transcription
Call analytics and medical transcription
Pre-recorded and live speech-to-text
Pre-recorded and live speech-to-text
Speech understanding and LLM-powered voice workflows
Speech understanding and LLM-powered voice workflows
User reviews
Editorial score
Distribution is estimated from our editorial score. Verified user reviews coming soon.
Use cases
Typical ways teams rely on this tool — from everyday tasks to specialized workflows.
- Voice agents and AI notetakers
- Call analytics and medical transcription
- Pre-recorded and live speech-to-text
- Speech understanding and LLM-powered voice workflows
Integrations
Reported connectors
Apps and services commonly connected out of the box or via official connectors.
- Python SDK
- TypeScript SDK
- Ruby SDK
- Go SDK
- RESTful API
- WebSocket API
Details
Category
Price
- Pay as you go from $0.15/hour
- $50 free credits for new accounts
Free version
Best for
- Voice agents and AI notetakers
- Call analytics and medical transcription
- Pre-recorded and live speech-to-text
Frequently asked questions
Assembly AI
Developer
Ready to get started?
Visit the Assembly AI website to explore plans and start your free trial.
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