AssemblyAI
APIs for accurate speech‑to‑text and audio intelligence, enabling developers to transcribe, understand, and act on voice data.
What is AssemblyAI?
AssemblyAI is an American AI company founded in 2017, offering a unified API platform for high‑accuracy speech‑to‑text and layered audio intelligence features such as speaker detection, sentiment analysis, summarization, PII redaction, topic detection, and LLM integration via its LLM Gateway. The platform emphasizes consumption‑based pricing and scalability, supporting both pre‑recorded and real‑time streaming audio workflows. As of early 2026, it processes hundreds of millions of audio hours annually and serves hundreds of thousands of developers and enterprise clients.
What you can do with it
Meeting transcription and analysis
Automating transcription of meetings with speaker labels, sentiment, key topics and summaries.
Voice‑agent and call‑center applications
Driving real‑time voice agents using streaming speech‑to‑text with intent understanding and speaker identification.
Content moderation and privacy compliance
Filtering profanity and redacting sensitive PII from audio or transcripts for compliance.
Multilingual transcription and translation
Transcribing and translating audio in many languages for global accessibility.
Podcast or media processing workflows
Generating searchable transcripts, chapters, topic tags, and summaries from recorded media.
Support‑analytics pipelines
Analyzing customer calls for sentiment, action items, and key phrases at scale using APIs.
Key features
- High‑accuracy speech‑to‑text across 99+ languages
- Real‑time streaming transcription with sub‑300 ms latency
- Speaker diarization and speaker identification by name/role
- Speech understanding features: sentiment, summarization, entities, topic detection
- Guardrails including profanity filtering, PII audio/text redaction, content moderation
- LLM Gateway enabling unified voice‑to‑LLM workflows
- Prompting capabilities and custom vocabulary/spelling adjustments
Screenshots
Inputs / Outputs
Strengths & Limitations
Strengths
Comprehensive audio intelligence stack
Beyond transcription, includes rich features such as speaker diarization, sentiment analysis, summarization, PII redaction, moderation, and entity/topic detection.
High transcription accuracy and multilingual support
Latest Universal‑3 Pro and Universal‑2 models deliver strong accuracy across multiple languages (6 languages for Pro, 99 for Universal‑2) and prompt‑based customization.
Flexible usage‑based pricing
Free trial credits with no credit card required, followed by transparent pay‑as‑you‑go billing with pro‑rata billing by the second and scalable rate limits.
LLM‑Gateway for voice‑to‑intelligence workflows
Integrates LLMs (such as GPT‑5.2, Gemini, Claude variants) directly with transcribed audio via one unified API call.
Strong compliance and security posture
Supports enterprise compliance with HIPAA, SOC 2 Type II, GDPR, ISO 27001, PCI‑DSS, EU data residency, and BAA options.
Scalable streaming API
Real‑time streaming with promptable Universal‑3 Pro Streaming (launched February 2026) and robust concurrency controls.
Limitations
Add‑on cost stacking
Base transcription is competitive, but advanced features quickly increase per‑hour cost significantly.
No standalone client app
Designed as an API platform—requires integration and tooling rather than a standalone transcription application.
No public launch date precision
While founded in 2017, no specific public launch day beyond year is broadly documented.
Complex pricing structure
Multiple models, add‑ons, and token‑based LLM gateway pricing may be challenging for budget forecasting.
Pricing & Plans
Model: Freemium
Free
Includes credits or allowances (≈185 hr pre‑recorded, 333 hr streaming), access to all core APIs and features, limited concurrency
Pay‑as‑you‑go
Usage‑based access to all models and add‑on capabilities, scalable concurrency, compliance options (HIPAA, EU residency)
Enterprise
Custom SLAs, dedicated support, self‑hosted or VPC deployments, compliance and scalability for regulated industries
Free tier includes approximately $50 in credits (~185 hours of pre‑recorded or 333 hours of streaming audio) with no credit card required; thereafter usage‑based pay‑as‑you‑go pricing starting around $0.15/hr for base transcription, plus additional per‑hour add‑on costs (e.g., speaker diarization, summarization, PII redaction); enterprise or volume discounts available on request.
Who it's for
Ideal for
Developers and enterprises needing a scalable, API‑driven platform for transcription and rich audio intelligence, especially for voice agents, call analytics, meeting summaries, or voice‑to‑AI workflows.
Not ideal for
Users seeking a simple, standalone transcription app without integration work or who require a fixed flat rate without variable feature costs.
What users say
- Developer‑friendly pricing
- High accuracy and reliability
- Rich feature set
- Enterprise readiness
Prompts & Results
›Transcribe a customer service call, include speaker diarization and summarization.
Transcript with Speaker A/B labels, summary of key issues discussed.
›Transcribe a medical consultation with medical mode enabled and redact PII.
Accurate transcription optimized for medical terms, with sensitive personal information redacted.
›Stream live meeting audio using Universal‑3 Pro Streaming with prompting for topic tagging.
Low‑latency transcript with embedded tags at segment boundaries indicating discussion topics.
›Transcribe interview audio, then use LLM Gateway to extract key themes.
Full transcript plus generated themes and insights from LLM applied over the transcribed text.
FAQ
How much does AssemblyAI cost after the free credits?+
After the initial ~$50 in free credits, pay‑as‑you‑go pricing applies: base models start around $0.15/hr (Universal‑2) or $0.21/hr (Universal‑3 Pro) plus hourly fees for add‑on features like speaker diarization ($0.02/hr), summarization ($0.03/hr), and PII redaction ($0.08/hr).
Do I need a credit card to start using AssemblyAI?+
No—AssemblyAI offers free usage credits at signup with no credit card required.
What input formats does AssemblyAI support?+
AssemblyAI processes both pre‑recorded audio and video files, as well as real‑time streaming audio.
Can I deploy AssemblyAI in regulated environments?+
Yes—AssemblyAI supports HIPAA BAA, SOC 2 Type II, GDPR, ISO 27001, PCI‑DSS, and offers EU data residency options.
Ratings & Reviews
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