Build confidently with 
industry-leading Speech AI models

AssemblyAI’s Universal models leads industry accuracy. Benchmarks report 94.07% word accuracy in English, 93.6% in Spanish, and 90.8% in German across diverse datasets. The API also returns per‑word confidence scores (0.0–1.0) to flag uncertain tokens for review.

Yes. AssemblyAI provides real-time streaming transcription via a secure WebSocket API. You can stream live audio and receive transcripts within a few hundred milliseconds. It supports use cases like live calls (e.g., Twilio). English is default, with a multilingual streaming model for EN/ES/FR/DE/IT/PT.

AssemblyAI supports 99 languages with its Universal model—covering Global/US/British/Australian English plus major world languages (e.g., Spanish, French, German, Italian, Portuguese, Dutch, Hindi, Japanese, Chinese, Korean, etc.). Universal-3 Pro currently supports English, Spanish, French, German, Italian and Portuguese. Automatic language detection and code‑switching are available. See the docs for the full list.

Yes. Use Custom Spelling to map words/phrases to your preferred spelling/format (supported across all languages and models). To improve recognition of industry terms or brands, use Keyterms Prompting to boost specific words/phrases; it's built in for pre-recorded STT and offered as an add-on for streaming.

Create a free AssemblyAI account, install the SDK (e.g., pip install assemblyai), and set aai.settings.api_key. Transcribe a file with aai.Transcriber().transcribe(...) or follow the Quickstart for streaming. You can also test features without code in the AssemblyAI Playground.

AssemblyAI uses usage-based pricing. Free tier: up to 185 hours of pre‑recorded and 333 hours of streaming. Pay‑as‑you‑go: Universal (pre‑recorded) $0.15/hr; Universal‑Streaming $0.15/hr; Universal-3 Pro $0.21/hr. See the pricing page for full, per‑feature rates.