AssemblyAI

Speech

AssemblyAI, founded in 2017 by Dylan Fox and headquartered in San Francisco, operates a voice AI platform that provides APIs for speech-to-text, speech understanding, and voice agent development.

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AssemblyAI provides APIs that convert audio to text and extract meaning from speech, enabling developers to build voice-enabled applications.

AssemblyAI, founded in 2017 by Dylan Fox and headquartered in San Francisco, operates a voice AI platform that provides APIs for speech-to-text, speech understanding, and voice agent development. As of early 2026, the company has raised a total of $115 million in funding, per PitchBook, with its most recent publicly disclosed round being a $50 million Series B in December 2023 led by Accel. The company reported 75 employees as of April 2023 (Contrary Research).

AssemblyAI's product suite includes pre-recorded and real-time speech-to-text APIs, a Speech Understanding API for summarization and content moderation, a Voice Agent API launched in early 2026, Guardrails for controlling model outputs, and an LLM Gateway. The company also offers a self-hosted deployment option. AssemblyAI positions itself as infrastructure for builders, targeting developers and enterprises that need to integrate voice capabilities into their products.

The company publishes a Voice Agent Report, and in its 2026 edition it noted that 87.5% of surveyed builders are actively building voice agents. AssemblyAI's customers include Zoom, which uses the platform to advance its AI research and development. The voice recognition market was valued at $18.39 billion in 2025 and is projected to reach $61.71 billion by 2031, a 22.38% CAGR, according to Mordor Intelligence data cited by AssemblyAI. The company faces competition from cloud providers' native speech services (AWS Transcribe, Google Cloud Speech-to-Text) and from specialized voice AI startups like PolyAI and Retell AI.

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Who buys this

  • Developers building voice agents and conversational AI products
  • Contact centers deploying conversation intelligence and quality assurance tools
  • Healthcare organizations needing medical transcription services
  • Media and content companies requiring automated transcription and captioning
  • Enterprise teams integrating voice interfaces into internal and customer-facing applications

Publicly disclosed clients

  • Zoom

Strengths and what to watch

Strengths

  • Raised $115 million total funding, including a $50 million Series B in December 2023, providing capital for model development and go-to-market expansion.
  • Product breadth covers the full voice AI stack—transcription, understanding, voice agents, guardrails, and LLM gateway—reducing the need for customers to stitch together multiple vendors.
  • Published research and market reports (e.g., 2026 Voice Agent Report) position the company as a thought leader in the voice AI category, attracting developer mindshare.

Watch for

  • Competition from hyperscalers: AWS Transcribe, Google Cloud Speech-to-Text, and Azure Speech Services offer similar capabilities, often bundled with broader cloud credits, which could pressure pricing and market share.
  • Customer concentration risk: Zoom is the only named enterprise client in public materials; over-reliance on a single high-profile customer could pose revenue risk if the relationship changes.
  • Funding gap: The last publicly disclosed round was December 2023; with $115 million raised and a competitive hiring market, the company may need to raise additional capital or demonstrate a clear path to profitability to sustain operations.

Key Information

Industry
Speech
Founded
2017
Headquarters
San Francisco

Frequently Asked Questions

What is AssemblyAI and what does it do?

AssemblyAI is a voice AI platform that provides APIs for converting audio to text and extracting meaning from speech. It enables developers to build voice-enabled applications with features like speech-to-text, speech understanding, and voice agent development.

How accurate is AssemblyAI's speech-to-text API?

AssemblyAI's speech-to-text API is designed for high accuracy, with 76% of builders in its 2026 Voice Agent Report rating accuracy as critical. The company continuously improves its models, though specific accuracy benchmarks are not publicly detailed in the provided source.

What products does AssemblyAI offer?

AssemblyAI offers pre-recorded and real-time speech-to-text APIs, a Speech Understanding API for summarization and content moderation, a Voice Agent API launched in early 2026, Guardrails for controlling outputs, and an LLM Gateway. It also provides self-hosted deployment options.

Who are AssemblyAI's main competitors?

AssemblyAI competes with cloud providers' native speech services like AWS Transcribe, Google Cloud Speech-to-Text, and Azure Speech Services. It also faces competition from specialized voice AI startups such as PolyAI and Retell AI, as noted in the company's own market reports.

How much funding has AssemblyAI raised?

AssemblyAI has raised a total of $115 million in funding, according to PitchBook. Its most recent publicly disclosed round was a $50 million Series B in December 2023 led by Accel. The company reported 75 employees as of April 2023.

What are common use cases for AssemblyAI?

Common use cases include building voice agents and conversational AI products, deploying conversation intelligence in contact centers, medical transcription for healthcare, automated transcription and captioning for media, and integrating voice interfaces into enterprise applications. Notable customer Zoom uses it for AI research.

Sources

  1. www.assemblyai.com — Product portfolio, customer list (Zoom), deployment options, use cases, and company positioning.
  2. www.assemblyai.com — Voice AI market data ($18.39B voice recognition market in 2025, $61.71B projected by 2031, 22.38% CAGR), VC investment figures ($2.1B in 2024), and mention of competitors PolyAI and Retell AI.
  3. www.assemblyai.com — Voice Agent Report findings: 87.5% of builders actively building voice agents, 76% rate speech-to-text accuracy as critical, and market projections ($2.4B in 2024 to $47.5B by 2032).
  4. pitchbook.com — Total funding of $115 million and list of 14 investors.
  5. research.contrary.com — Founding date (Jan 2017), headquarters (San Francisco), total funding ($63.1M as of April 2023), stage (Series B), employee count (75), and product description.
  6. techcrunch.com — December 2023 $50M Series B funding round led by Accel.