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AssemblyAI

assemblyai.com

From $0.15/mo Free plan WebAPISelf-hosted
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Spec score 8.8 #8 of 46 in Transcription Software

What it is

AssemblyAI provides Voice AI models and APIs for speech-to-text, speech understanding, and voice applications. Its Speech Understanding API can identify and diarize speakers, summarize speech, extract action items and key phrases, detect sentiment, entities, and topics, and handle formatting, language detection, translation, PII redaction, and content moderation. The platform lists support for 99 languages and translation into 86. It offers streaming and voice-agent latency below 300ms and states that it processes more than 800 million API calls per month. Use its managed cloud or self-host models in your own environment; the service also lists API access and integrations including Twilio, Zoom RTMS, Zapier, and LangChain. Security options include TLS 1.2+ in transit, AES-256 at rest, zero data retention, and opting out of model training. A free tier is available. Pay-as-you-go billing is based on usage, with monthly invoices and no minimum commitments. Universal-2 is listed at $0.15 per hour of audio; Universal-3.6 Pro Realtime is $0.45 per hour.

Spec sheet

What it does
AssemblyAI provides Voice AI models and APIs for speech-to-text, speech understanding, and voice applications.Read 1 Oct 2026 · assemblyai.com
Deployment
Customers can run AssemblyAI in its managed cloud or self-host the models inside their own environment.Read 1 Oct 2026 · assemblyai.com
Free plan
NoRead 20 Sep 2026 · assemblyai.com
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.Read 1 Oct 2026 · assemblyai.com
Security
AssemblyAI offers TLS 1.2+ encryption in transit, AES-256 encryption at rest, zero data retention, and an opt-out from model training.Read 1 Oct 2026 · assemblyai.com
Compliance
AssemblyAI maintains an annually audited SOC 2 Type 2 report and conducts annual third-party penetration tests.Read 1 Oct 2026 · assemblyai.com
API access
YesRead 20 Sep 2026 · assemblyai.com
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.Read 1 Oct 2026 · assemblyai.com
Developer support
AssemblyAI provides documentation, an API reference, cookbooks, support resources, a changelog, and a service-status page.Read 1 Oct 2026 · assemblyai.com
Export formats
SRT,VTTRead 20 Sep 2026 · assemblyai.com
Language coverage
The platform states coverage across 99 languages and translation into 86 languages.Read 1 Oct 2026 · assemblyai.com
Languages supported
99Read 20 Sep 2026 · assemblyai.com
Latency
AssemblyAI states sub-300ms latency for streaming and voice agents.Read 1 Oct 2026 · assemblyai.com
Scale
AssemblyAI states that its platform processes more than 800 million API calls per month.Read 1 Oct 2026 · assemblyai.com
SDKs
Official documentation provides Python and JavaScript SDK guidance.Read 1 Oct 2026 · assemblyai.com
Speaker identification
YesRead 20 Sep 2026 · assemblyai.com
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.Read 1 Oct 2026 · assemblyai.com
Timestamp support
YesRead 20 Sep 2026 · assemblyai.com

Plans and prices

Free credits Free $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 $0.15 a month Billed monthly based on actual usage; audio is prorated to the second 99 languages · 200+ concurrent pre-recorded transcriptions Read 20 Sep 2026 · assemblyai.com
Pay as you go — Universal-3.5 Pro $0.21 a month Billed monthly based on actual usage; audio is prorated to the second 18 languages · 200+ concurrent pre-recorded transcriptions Read 20 Sep 2026 · assemblyai.com
Pay as you go — Universal-Streaming $0.15 a month Billed monthly based on actual usage 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 $0.45 a month Billed monthly based on actual usage 18 languages · 100+ starting sessions per minute on paid accounts Read 20 Sep 2026 · assemblyai.com
Free tier Free 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-2 $0.15 a month per hour of audio 99 languages · lower-price speech-to-text model Read 1 Oct 2026 · assemblyai.com
Universal-Streaming $0.15 a month per hour of audio English-only realtime transcription Read 1 Oct 2026 · assemblyai.com
Universal-Streaming Multilingual $0.15 a month per hour of audio English, Spanish, German, French, Portuguese, and Italian Read 1 Oct 2026 · assemblyai.com
Universal-3.5 Pro $0.21 a month per hour of audio 18 languages · custom rate limits available Read 1 Oct 2026 · assemblyai.com
Universal-3.6 Pro Realtime $0.45 a month per hour of audio 32 languages · context carryover and conversation memory Read 1 Oct 2026 · assemblyai.com
Voice Agent API $4.50 a month per hour of connected conversation time Managed orchestration and hosting · no per-layer add-ons or concurrency fees Read 1 Oct 2026 · assemblyai.com

Every AssemblyAI plan and price →

Strong points and limits

Strong points

  • Supports transcription across 99 languages.
  • Can self-host models or use managed cloud.
  • Includes speaker identification and timestamp support.
  • Offers free credits and a free tier.
  • Python and JavaScript SDK guidance is available.

Limits

  • Universal-3.6 Pro Realtime costs $0.45 per hour.
  • The Universal-3.5 Pro plans list 18 languages.
  • Free credits have connection and transcription limits.

Who it suits

It suits developers building transcription, speech-understanding, or voice applications who need API access, language coverage, or self-hosting. The free tier may suit those starting with limited transcription or streaming usage.

Verdict

AssemblyAI combines transcription and speech-understanding capabilities with API access, self-hosting, and usage-based billing. Check the specific model’s language coverage and listed limits against your workload.

Where Specifiction places it

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