AssemblyAI

AssemblyAI is a Voice AI platform that turns speech from calls, meetings, podcasts, and voice agents into accurate text using simple developer APIs. It offers both pre-recorded and realtime transcription, so you can process saved audio files or capture live conversations as they happen.

Its flagship Universal-3.5 Pro model delivers strong accuracy across 18 languages, handles multiple speakers, and understands medical and technical terms. Beyond plain transcription, the platform adds understanding features like summaries, sentiment, topics, and translation.

For teams building voice agents, AssemblyAI bundles speech-to-text, a tuned language model, and text-to-speech into one Voice Agent API, removing the need to stitch together separate tools.

Pricing is usage based, charged per hour of audio processed, with custom plans available for larger teams needing higher volume or extra support.

• Pre-recorded and realtime speech-to-text

• Single-call Sync API for short clips

• Speaker diarization and labeling

• Support for up to 99 languages

• Summaries, sentiment, and topic detection

• Translation and entity detection

• PII redaction and content moderation

• End-to-end Voice Agent API

• Medical Mode for healthcare audio

• Python and JavaScript SDKs