AssemblyAI API
Speech-to-text API with built-in LLM-powered features including transcription, speaker diarization, sentiment analysis, summarization, and entity detection in audio and video content.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
HIPAA, SOC2, GDPR compliant. Single API key with full access - no scope granularity. Audio data processed on AssemblyAI servers - data retention policy important for sensitive audio.
⚡ Reliability
Best When
An agent needs to extract structured information from audio/video with high accuracy and built-in NLP features beyond basic transcription.
Avoid When
You need real-time translation, on-premises processing, or sub-100ms STT latency.
Use Cases
- • Transcribing audio/video files with high accuracy for agent knowledge extraction
- • Speaker diarization to identify and separate speakers in multi-party recordings
- • Real-time streaming transcription for live agent monitoring
- • Auto-generating meeting summaries and action items from audio
- • Sentiment and entity analysis of spoken content
Not For
- • Real-time translation (AssemblyAI is English-first, though multilingual support is growing)
- • Extremely low-latency STT requirements
- • On-premises or air-gapped deployments
Interface
Authentication
Single API key via Authorization header. Same key for all features.
Pricing
Agent Metadata
Known Gotchas
- ⚠ Transcription is async - agents must poll for completion or use webhooks; no synchronous mode for long audio
- ⚠ Audio must be publicly accessible via URL or uploaded first via upload endpoint
- ⚠ LeMUR (LLM analysis) costs extra beyond base transcription
- ⚠ Webhook verification not enforced - must manually validate webhook signatures
Alternatives
Full Evaluation Report
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Scores are editorial opinions as of 2026-03-07.