AssemblyAI
AI speech-to-text API with built-in audio intelligence features for developers.
Quick take
AssemblyAI is the best choice when you need more than transcription. The LeMUR framework turns a speech-to-text API into a conversation understanding platform. For pure transcription on price and speed, Deepgram wins. For transcription plus intelligence, AssemblyAI wins. Many teams end up using both: Deepgram for real-time streaming and AssemblyAI for post-call analysis.
AssemblyAI scorecard
How we gradeSpeech API with the deepest audio intelligence toolkit.
Overview
AssemblyAI is a speech-to-text API that competes directly with Deepgram but differentiates with LLM-powered post-processing features. Beyond basic transcription, AssemblyAI offers LeMUR (a framework for applying large language models to transcripts) which enables summarization, question answering, action item extraction, and custom prompts. The company has raised significant funding and focuses exclusively on the developer API market, not consumer products.
Strengths & limitations
Strengths
- +Rich audio intelligence features beyond transcription
- +LeMUR enables Q&A on audio content
- +Excellent developer documentation
Limitations
- –Higher per-minute cost than Deepgram
- –No real-time streaming (batch only)
- –English-focused accuracy
Pricing
Pay As You Go: from $0.00025/second (~$0.015/min) for transcription. LeMUR usage is billed separately based on input/output tokens. Free tier available with limited hours. Enterprise plans with custom pricing for high volume and on-premise needs.
Who it's for
Developers who need transcription plus LLM-powered intelligence in one API. Teams building meeting summarization, coaching, or compliance features who want to avoid wiring together a separate transcription service and LLM. If you only need raw transcription and care about cost, Deepgram is cheaper. If you want the intelligence layer built in, AssemblyAI saves development time.
Verdict
A- · 83/100AssemblyAI is the best choice when you need more than transcription. The LeMUR framework turns a speech-to-text API into a conversation understanding platform. For pure transcription on price and speed, Deepgram wins. For transcription plus intelligence, AssemblyAI wins. Many teams end up using both: Deepgram for real-time streaming and AssemblyAI for post-call analysis.
Key features
- Speech-to-text API
- LeMUR (LLM for audio)
- PII redaction
- Topic and sentiment detection
- Speaker diarization
What users say
The API setup was super quick, about 30 minutes from account creation to usage.
G2
Customization is limited; fine-tuning for domain-specific vocabulary isn't as deep as you'd hope.
G2
