# AssemblyAI Review

> AssemblyAI review: Accuracy-led voice AI API for developers and voice agents. Verified pricing, features, and the strongest alternatives in Speech-to-text APIs.

![AssemblyAI logo](https://www.versusref.com/logos/assemblyai.png)

Accuracy-led voice AI API for developers and voice agents

Among the 43 speech-to-text tools we track, AssemblyAI has the 12th-widest language coverage - a fit for multilingual and localization projects.

See pricing · facts verified Jul 20, 2026

## What we know about AssemblyAI

AssemblyAI is a speech-to-text apis platform: accuracy-led voice AI API for developers and voice agents. This profile tracks every AssemblyAI fact we have verified, each linked to a primary source and dated.

AssemblyAI does not publish a public per-minute rate we have been able to verify, so the price figure here stays blank until we can confirm one. We would rather show nothing than a guessed number; if you have a current AssemblyAI quote, it is the fastest way for us to close that gap.

On capabilities, AssemblyAI covers language auto-detection, word-level timestamps, custom vocabulary / keyterm boosting, entity detection, sentiment analysis, and summarization endpoint. Each of those is verified against AssemblyAI's own docs or dashboard, not marketing copy.

For compliance, with AssemblyAI: SOC 2 Type II is in place. If you are in a regulated space, confirm the current posture with AssemblyAI before you commit, since these change plan by plan.

AssemblyAI ranks the 12th-widest language coverage of the 43 speech-to-text tools we track, so where it lands for you depends on which of those matters more.

In total we track 31 verified facts for AssemblyAI today, each linking the primary source it came from so you can check our work - and vendor claims we have not measured ourselves are labeled as such on the AssemblyAI fact sheet below.

## AssemblyAI pricing

Published rates: batch $0.0035/min · streaming $0.0075/min, verified Jul 20, 2026 ([source](https://www.assemblyai.com/pricing)).

| Monthly volume | Batch bill | Streaming bill |
| --- | --- | --- |
| 1K min/mo | $3.50 | $7.50 |
| 10K min/mo | $35 | $75 |
| 100K min/mo | $350 | $750 |

Sticker rates only; diarization and PII redaction add-ons price in the stack builder.

## Fact sheet

### Pricing

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Batch price per audio minute | 0.004 $/audio-min | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Streaming price per audio minute | 0.008 $/audio-min | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Pricing model | usage | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Free tier quota | $50 one-time signup credit, no credit card required | Jul 20 | [source](https://www.assemblyai.com/llms/pricing.md) |
| Published volume discounts | Custom tiered pricing via sales; no published rates | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Concurrency on base plan | Async: 200+ concurrent jobs; streaming: 100 new streams/min | Jul 20 | [source](https://www.assemblyai.com/docs/pre-recorded-audio/rate-limits) |
| Extra concurrency cost | Custom higher limits at no additional cost | Jul 20 | [source](https://www.assemblyai.com/docs/pre-recorded-audio/rate-limits) |

### Capabilities

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| WER (third-party benchmark) | 3.02 % WER | Jul 20 | [source](https://artificialanalysis.ai/speech-to-text) |
| WER (vendor-claimed) | ~5.6 % WER | Jul 20 | [source](https://www.assemblyai.com/llms/models.md) |
| Streaming latency (vendor-claimed) | ~150 ms | Jul 20 | [source](https://www.assemblyai.com/llms/models.md) |
| Languages supported | 99 | Jul 20 | [source](https://www.assemblyai.com/docs/pre-recorded-audio/supported-languages) |
| Language auto-detection | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) |
| Speaker diarization | ◑  Paid add-on | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Diarization add-on price per minute | 0 $/audio-min | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| PII redaction | ◑  Paid add-on | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| PII redaction add-on price per minute | 0.001 $/audio-min | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Word-level timestamps | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Custom vocabulary / keyterm boosting | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Entity detection | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Sentiment analysis | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Summarization endpoint | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Speech translation | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/pricing) |
| Priced audio-intelligence add-ons | 13 per-hour add-ons (Speech Understanding + Guardrails) | Jul 20 | [source](https://www.assemblyai.com/pricing) |

### Compliance & trust

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| HIPAA BAA available | ✓  Included | Jul 20 | [source](https://www.assemblyai.com/docs/faq/can-you-sign-a-baa) |
| SOC 2 Type II | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/security) |
| GDPR / EU data residency | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/security) |
| Self-host / on-prem option | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/docs/streaming/self-hosted-streaming) |

### Build experience

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Official SDKs | Python, JavaScript/Node (official) | Jul 20 | [source](https://www.assemblyai.com/docs/agent-instructions.md) |
| Max file size / duration | 5 GB / 10 hr per file; 2.2 GB via upload endpoint | Jul 20 | [source](https://www.assemblyai.com/docs/faq/are-there-any-limits-on-file-size-or-file-duration-for-files-submitted-to-the-api) |
| Supported audio formats | 30+ audio + video formats (mp3, wav, flac, m4a, mp4, mov) | Jul 20 | [source](https://www.assemblyai.com/docs/faq/what-audio-and-video-file-types-are-supported-by-your-api) |
| Websocket streaming API | ✓  Yes | Jul 20 | [source](https://www.assemblyai.com/llms/pricing.md) |

## AssemblyAI head-to-head

| Comparison | Record | Per use case |
| --- | --- | --- |
| [AssemblyAI vs Deepgram](https://www.versusref.com/stt/assemblyai-vs-deepgram/) | won 3 · lost 0 · tied 3 | Call Centers: won; Developers: won; Dictation: tie; Medical: tie; Meetings: won; Self-Hosted: tie |
| [AssemblyAI vs OpenAI Whisper (API)](https://www.versusref.com/stt/assemblyai-vs-whisper/) | won 4 · lost 1 · tied 1 | Developers: won; Dictation: tie; Medical: won; Meetings: won; Self-Hosted: lost; Voice Agents: won |
| [AssemblyAI vs ElevenLabs Scribe](https://www.versusref.com/stt/assemblyai-vs-elevenlabs-scribe/) | won 3 · lost 2 · tied 1 | Call Centers: won; Developers: lost; Dictation: tie; Medical: won; Self-Hosted: won; Voice Agents: lost |
| [AssemblyAI vs Speechmatics](https://www.versusref.com/stt/assemblyai-vs-speechmatics/) | won 3 · lost 2 · tied 2 | Call Centers: lost; Developers: lost; Dictation: tie; Medical: won; Meetings: won; Self-Hosted: tie; Voice Agents: won |
| [AssemblyAI vs Gladia](https://www.versusref.com/stt/assemblyai-vs-gladia/) | won 4 · lost 0 · tied 3 | Call Centers: won; Developers: won; Dictation: tie; Medical: tie; Meetings: won; Self-Hosted: tie; Voice Agents: won |
| [AssemblyAI vs Rev AI](https://www.versusref.com/stt/assemblyai-vs-rev/) | won 4 · lost 0 · tied 2 | Developers: tie; Dictation: tie; Medical: won; Meetings: won; Self-Hosted: won; Voice Agents: won |
| [AssemblyAI vs Soniox](https://www.versusref.com/stt/assemblyai-vs-soniox/) | won 4 · lost 0 · tied 1 | Dictation: tie; Medical: won; Meetings: won; Self-Hosted: won; Voice Agents: won |

Source: https://www.versusref.com/stt/tools/assemblyai/