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AssemblyAI
What it is
AssemblyAI provides Voice AI models and APIs for speech-to-text, speech understanding, and voice applications. Its Speech Understanding API includes speaker diarization and identification, summaries, action items, sentiment analysis, key phrases, entity and topic detection, formatting, language detection, translation, personally identifiable information redaction, and content moderation. The platform states that it supports 99 languages and translation into 86. Customers can use AssemblyAI through its managed cloud or self-host models in their own environment. The company states sub-300ms latency for streaming and voice agents, and lists integrations such as Twilio, Zoom RTMS, Zapier, LangChain, and Vercel AI SDK. Documentation includes Python and JavaScript SDK guidance. Listed protections include TLS 1.2+ encryption in transit, AES-256 encryption at rest, zero data retention, and an option to opt out of model training. A free tier is available, while usage-based plans are billed monthly. Rates listed include $0.15 a month for Universal-2 and $0.45 a month for Universal-3.6 Pro Realtime, billed per hour of audio. Free credits include $50 in audio credits, subject to connection and transcription limits.
For and against
For
- Supports speech features including summaries and sentiment analysis.
- Lists coverage across 99 languages.
- Offers managed cloud or self-hosted deployment.
- Includes Python and JavaScript SDK guidance.
- Free credits include $50 in audio credits.
Against
- Some models cover fewer languages than others.
- Free access has streaming and transcription limits.
- Voice Agent API is listed at $4.50 a month per hour of connected conversation.
The verdict
AssemblyAI offers speech transcription and analysis through APIs, with several deployment and billing options. Compare model language coverage and listed usage rates against the requirements of your application.
Who it suits
AssemblyAI suits developers building transcription, speech-analysis, or voice applications who want API access. Teams can choose managed cloud use or self-hosting, with documentation for Python and JavaScript.
Plans and prices
Free credits
$50 in audio credits · 5 new streaming connections per minute · 5 concurrent pre-recorded transcriptions
Read 20 Sep 2026 · support.assemblyai.com
Pay as you go — Universal-2
99 languages · 200+ concurrent pre-recorded transcriptions
Read 20 Sep 2026 · assemblyai.com
Pay as you go — Universal-3.5 Pro
18 languages · 200+ concurrent pre-recorded transcriptions
Read 20 Sep 2026 · assemblyai.com
Pay as you go — Universal-Streaming
5 new streams per minute on free accounts · 100+ starting sessions per minute on paid accounts
Read 20 Sep 2026 · assemblyai.com
Pay as you go — Universal-3.5 Pro Realtime
18 languages · 100+ starting sessions per minute on paid accounts
Read 20 Sep 2026 · assemblyai.com
Free tier
Up to 185 hours pre-recorded transcription · up to 333 hours streaming transcription · 5 new streaming connections per minute
Read 1 Oct 2026 · assemblyai.com
Universal-Streaming
English-only realtime transcription
Read 1 Oct 2026 · assemblyai.com
Universal-2
99 languages · lower-price speech-to-text model
Read 1 Oct 2026 · assemblyai.com
Universal-Streaming Multilingual
English, Spanish, German, French, Portuguese, and Italian
Read 1 Oct 2026 · assemblyai.com
On the record
- API access
- Yesassemblyai.com · read 20 Sep 2026
- Billing
- Pay-as-you-go billing has no minimum commitments, upfront fees, contracts, or monthly subscription requirement, and invoices are generated monthly for prior usage.assemblyai.com · read 1 Oct 2026
- Compliance
- AssemblyAI maintains an annually audited SOC 2 Type 2 report and conducts annual third-party penetration tests.assemblyai.com · read 1 Oct 2026
- Deployment
- Customers can run AssemblyAI in its managed cloud or self-host the models inside their own environment.assemblyai.com · read 1 Oct 2026
- Developer support
- AssemblyAI provides documentation, an API reference, cookbooks, support resources, a changelog, and a service-status page.assemblyai.com · read 1 Oct 2026
- Export formats
- SRT,VTTassemblyai.com · read 20 Sep 2026
- Integrations
- Official integrations include LiveKit, Pipecat, OpenRouter, Zapier, Make, n8n, Postman, Recall.ai, Zoom RTMS, Telnyx, Twilio, Amazon Connect, Genesys Cloud, LangChain, Vercel AI SDK, Power Automate, Semantic Kernel, Cloudflare, Bubble, Pipedream, and Drupal.assemblyai.com · read 1 Oct 2026
- Languages supported
- 99assemblyai.com · read 20 Sep 2026
- Language coverage
- The platform states coverage across 99 languages and translation into 86 languages.assemblyai.com · read 1 Oct 2026
- Latency
- AssemblyAI states sub-300ms latency for streaming and voice agents.assemblyai.com · read 1 Oct 2026
- Scale
- AssemblyAI states that its platform processes more than 800 million API calls per month.assemblyai.com · read 1 Oct 2026
- SDKs
- Official documentation provides Python and JavaScript SDK guidance.assemblyai.com · read 1 Oct 2026
- Security
- AssemblyAI offers TLS 1.2+ encryption in transit, AES-256 encryption at rest, zero data retention, and an opt-out from model training.assemblyai.com · read 1 Oct 2026
- Speaker identification
- Yesassemblyai.com · read 20 Sep 2026
- Speech features
- Its Speech Understanding API supports speaker diarization, speaker identification, summarization, action items, sentiment analysis, key phrases, entity detection, topic detection, formatting, language detection, translation, PII redaction, and content moderation.assemblyai.com · read 1 Oct 2026
- Timestamp support
- Yesassemblyai.com · read 20 Sep 2026
- What it does
- AssemblyAI provides Voice AI models and APIs for speech-to-text, speech understanding, and voice applications.assemblyai.com · read 1 Oct 2026
