AssemblyAI
Developer speech-to-text API for accurate transcription and audio intelligence.
Free credits; usage-based API pricing for developers.
What AssemblyAI does
AssemblyAI is a speech-to-text platform in the audio category of AI tools, aimed at developers rather than end users. Its core is a transcription API that converts pre-recorded or live audio into accurate text, with support for speaker diarization so you can tell who said what. You send audio to the API and receive structured transcripts back, ready to store, search or display in your own product.
Beyond raw transcription, AssemblyAI layers on audio intelligence models: automatic summarization, topic detection, content moderation and more. Its LeMUR framework lets you run large-language-model tasks such as Q&A and custom summaries directly over transcripts, turning spoken audio into structured, queryable data.
Who it is for
AssemblyAI is built for engineering teams adding voice features to applications, from meeting-notes tools and call analytics to media platforms and accessibility captions. Because it is API-first, it fits into custom pipelines rather than offering a consumer editing interface. Pricing is pay-as-you-go with free starter credits, so small projects can prototype cheaply while larger workloads scale on usage. If you need reliable, programmable transcription plus audio understanding, it is a leading developer option.
Key features
- High-accuracy speech-to-text for pre-recorded audio and video
- Real-time streaming transcription over WebSockets
- Speaker diarization to label who said what
- Audio intelligence: summarization, topic detection and content safety
- LLM-powered analysis over transcripts via its LeMUR framework
- Simple REST API with SDKs and pay-as-you-go pricing
Pros & cons
👍 Pros
- Accurate transcription with rich audio-understanding features in one API
- Developer-friendly docs, SDKs and usage-based billing
👎 Cons
- Built for developers, so no polished end-user editing app
- Costs scale with audio volume on heavy workloads
AssemblyAI — FAQ
Is AssemblyAI free?
New accounts get free credits to test the API. After that, billing is usage-based per hour of audio processed.
Does AssemblyAI support real-time transcription?
Yes. Alongside async transcription of files, it offers real-time streaming speech-to-text over WebSockets.
What languages does AssemblyAI support?
Its models support many languages for transcription, with capabilities varying by model and feature.
What is AssemblyAI used for?
Developers use it to transcribe calls, meetings and media, and to add summaries, topics and speaker labels to audio apps.
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