# AssemblyAI

> Voice AI infrastructure for builders

Source: https://dailyaitools.ai/tools/assemblyai/ (dailyaitools, a tracker of AI tools; no ratings or reviews)

## Key facts

- Category: Audio
- Price: Free plan, then $0.02 usage-based
- Free plan: Yes, free plan, then $0.02 usage-based
- Works on: Web, API
- Website: https://www.assemblyai.com
- Verification: Under review since October 19, 2026: the last check did not confirm every detail.

## What it is

AssemblyAI provides production-ready Voice AI infrastructure for developers, featuring speech-to-text, streaming transcription, guardrails, and voice agent APIs. The platform handles complex audio processing tasks such as language detection, formatting, speaker identification, and medical transcription. It operates on a pay-as-you-go usage pricing model alongside a free trial signup option, with enterprise custom configurations available. Users can integrate these capabilities across various applications through its comprehensive developer API.

## Plans

| Plan | Price | Free-plan limit or note |
| --- | --- | --- |
| Free | Free | Start free, pay-as-you-go after that – no commitments required. |
| Speaker Diarization | $0.02 usage-based |  |
| Keyterms Prompting | $0.05 usage-based |  |
| Prompting | $0.05 usage-based |  |
| Universal-2 | $0.15 usage-based |  |
| Medical Mode | $0.15 usage-based |  |
| Universal-3.5 Pro | $0.21 usage-based |  |
| Pro | $0.21 usage-based | Pay as you go for Universal-3.5 Pro pre-recorded speech-to-text |
| Pay as you go | Custom |  |
| Custom | Custom |  |
| Enterprise | Custom | Custom rate limits, enhanced concurrency, and enterprise-grade flexibility |

Prices as printed on https://www.assemblyai.com/pricing. Nothing is converted or annualized.

## Features

- Pre-recorded and real-time streaming speech-to-text transcription
- Speaker diarization to segment utterances by speaker
- LLM-powered Speech Understanding and LLM Gateway
- Custom keyterms prompting and Medical Mode for specialized terminology

## Good fit for

- Building real-time voice agents
- Transcribing pre-recorded audio files with high accuracy
- Performing call analytics and medical transcription

## Questions

### Is AssemblyAI free?

Yes, AssemblyAI has a free plan. Paid plans start at $0.02 usage-based.

### How much does AssemblyAI cost?

AssemblyAI lists 11 plans: Free, Speaker Diarization at $0.02 usage-based, Keyterms Prompting at $0.05 usage-based, Prompting at $0.05 usage-based, Universal-2 at $0.15 usage-based, Medical Mode at $0.15 usage-based, Universal-3.5 Pro at $0.21 usage-based, Pro at $0.21 usage-based, Pay as you go (custom pricing), Custom (custom pricing), Enterprise (custom pricing).

### What models does AssemblyAI offer for transcription?

AssemblyAI offers flagship models such as Universal-3.5 Pro for both async and realtime audio, as well as Universal-2 supporting 99 languages.

### What additional features are available for speech-to-text APIs?

Available add-ons include keyterms prompting, plain language prompting, speaker diarization, and an optimized Medical Mode.

### How can I deploy AssemblyAI models?

AssemblyAI supports deployment options through its Voice AI Cloud as well as self-hosted infrastructure.

## Recorded pricing changes

- 2026-08-17: AssemblyAI added the Free plan at free.
- 2026-08-17: AssemblyAI added the Pro plan at $0.21.
- 2026-08-17: AssemblyAI added the Enterprise plan at custom pricing.
- 2026-08-10: AssemblyAI added the Pay as you go plan at custom pricing.
- 2026-08-10: AssemblyAI added the Custom plan at custom pricing.

## Sources

- https://www.assemblyai.com/llms.txt
- https://www.assemblyai.com
- https://www.assemblyai.com/pricing

Listed July 31, 2026, updated August 17, 2026.