Companies

AssemblyAI

assemblyai.com

AssemblyAI provides production-grade speech and voice AI APIs for developers building voice-enabled products.

HQSan Francisco, California, United States
Employees51-200
Funding$115M
18 active roles
Profile 6mo agoJobs checked 17h ago
AI / MLFoundation Model ProviderB2B SaaSSeries C$50M-$200M

About

AssemblyAI builds Voice AI infrastructure and production-grade APIs that let developers transcribe, understand, and act on speech. It sells primarily to software teams and enterprise customers, differentiating through highly accurate speech recognition for real-world audio, scalable real-time and prerecorded processing, and developer-friendly APIs.

Market

AssemblyAI competes in the developer-focused Voice AI and speech-intelligence infrastructure market, providing production-grade APIs for transcription, voice agents, and speech understanding. It positions itself as a complete Speech AI platform differentiated by accurate, fast, reliable transcription plus integrated capabilities such as real-time processing, sentiment analysis, speaker detection, and customizable language models. Its competitive set includes both specialized speech providers such as Deepgram and broad cloud platforms such as Microsoft Azure and Google Cloud.

Target Customers

AssemblyAI primarily serves app builders and software development teams building voice-enabled products, including teams that need accurate speech recognition, scalable infrastructure, and developer-friendly APIs. Its customer base spans developer-led product teams and enterprise customers, with engineering and product leaders as likely buyers.

At a Glance

Problem

Voice data from calls, meetings, podcasts, and call-center recordings contains valuable customer and operational information, but audio is difficult for software to search, analyze, and act on without accurate transcription and interpretation. The pain is especially acute in high-volume workflows: every additional minute of audio creates review and processing work, while delays, poor accuracy, and integration effort reduce the value of the data. The main use case is turning conversational recordings into searchable transcripts and actionable insights for sales, support, and operations.

Product / Service

AssemblyAI provides production-grade Speech AI infrastructure through developer-facing APIs rather than a standalone end-user application. Customers can upload prerecorded audio or stream audio in real time to obtain speech-to-text transcription, speech understanding, and related capabilities such as voice-agent functionality, guardrails, and an LLM gateway. Its API-first model lets developers embed these capabilities into their own products and push transcripts and extracted insights into systems such as CRMs and sales-engagement tools.

The business model is B2B and usage-based, allowing customers to scale processing with their audio volumes instead of building and operating speech models themselves. The benefit is a faster path from raw voice data to product features and business workflows, with AssemblyAI absorbing the complexity of model development, production deployment, and speech-processing infrastructure.

Market

AssemblyAI competes in the Speech AI and Voice AI infrastructure market, particularly APIs for speech-to-text, real-time transcription, and speech understanding. Its competitive set includes large cloud platforms such as Microsoft Azure Speech Service, Google Cloud Speech-to-Text, and AWS Transcribe, as well as specialist providers such as Deepgram; Gladia and ElevenLabs are adjacent alternatives in the broader developer speech-AI ecosystem. Differentiation is centered on model quality, latency, scale, ease of integration, and the breadth of downstream speech-understanding capabilities.

The company is not pre-revenue: available company and investor materials cite more than 200,000 developers using its API and over 5,000 paying customers. AssemblyAI also announced a $50 million Series C in December 2023, bringing total funding to $115 million. These figures indicate meaningful commercial traction and substantial investor backing, although the available evidence does not provide current revenue or profitability figures.

Founders & Leadership

Dylan FoxFounder
Founder & CEO
Jessi WatersChief Operating Officer
Alex KromanChief Product and Technology Officer
Ryan SeamsVP, Customer Solutions

Funding History

2017-01
Seed$7M (implied)

Not disclosed

2022-03
Series A$28M

Accel

2022-07
Series B$30M

Insight Partners

2023-12
Series C$50M

Accel

Recent News

2026-07-15product
How to choose the best speech-to-text API for voice agents

AssemblyAI positions Universal-3.5 Pro Realtime as its current streaming flagship and the speech foundation beneath its Voice Agent API.

2026-06-29partnership
Announcing the AssemblyAI integration for LlamaIndex.TS

AssemblyAI announced an integration with LlamaIndex.TS, extending its speech AI capabilities into the LlamaIndex ecosystem.

2026-06-23product
Universal-3.5 Pro Realtime vs. Voice Agent API: Which one should you actually build on?

AssemblyAI compared its direct Universal-3.5 Pro Realtime model with the bundled Voice Agent API. The realtime model offers roughly 300 ms end-of-turn detection, while the Voice Agent API bundles speech-to-text, an LLM, and text-to-speech at a flat $4.50 per hour.

2026-06-09product
One stream, two jobs: introducing SpeakerRevision

AssemblyAI introduced SpeakerRevision as a one-stream solution designed to provide both streaming transcription and speaker-related revision capabilities.

2026-05-01product
AssemblyAI April 2026 recap

AssemblyAI recapped its April launches, highlighting its most accurate streaming model yet and the full Voice Agent API.

2026-04-29product
Introducing our Voice Agent API

AssemblyAI launched a complete voice-agent pipeline built on its own models and exposed through a single WebSocket. The API includes developer features such as tool calling and session resumption.

2026-02-11
Voice AI in 2026: Inside the companies and investments shaping the future of speech

AssemblyAI examined the voice-AI market, reporting $2.1 billion in 2025 venture funding and highlighting companies and specialization across healthcare, sales, and customer experience.

2026-02-04
Inside AssemblyAI's NYC voice agents January 2026 meetup

More than 100 voice-AI builders gathered at AssemblyAI's New York City office to discuss production lessons, failure points for voice agents, and predictions for 2026.

2026-02-03product
Introducing Universal-3 Pro: A new class of speech language model optimized for Voice AI

AssemblyAI launched Universal-3 Pro, a promptable speech model whose behavior can adapt to instructions. The model supports capabilities such as audio tagging, disfluency capture, and speaker labeling through prompting.

2026-01-22
New 2026 insights report: What actually makes a good voice agent

AssemblyAI published a 2026 insights report focused on the characteristics and evaluation of effective voice agents.

Active Roles

18
Washington D.C./Engineering/2d ago
Chicago/Engineering/2d ago
Toronto/Engineering/2d ago
New York/Engineering/2d ago
Remote - New York/Engineering/2d ago
United Kingdom/Engineering/6d ago
North America /Engineering/6d ago
San Francisco/Operations/6d ago
New York /Legal/7d ago
New York City/Engineering/14d ago
San Francisco/Engineering/14d ago
Chicago/Engineering/14d ago
Los Angeles/Engineering/14d ago
Seattle/Engineering/14d ago
Denver/Engineering/14d ago
United States /Engineering/21d ago
Remote/Engineering/100d ago
Remote - San Francisco OR New York/Sales/128d ago

Business Model

AssemblyAI monetizes its speech and voice AI APIs primarily through pay-as-you-go usage-based pricing, with no contracts, minimums, or monthly subscriptions. It offers free API access/trials and custom enterprise plans for larger customers.

Products

Pre-recorded speech-to-text APIStreaming speech-to-text / real-time transcriptionVoice Agent APISpeech UnderstandingGuardrailsLLM Gateway

Customers

ZoomSiroGrainThe Wall Street Journal (WSJ)NBC UniversalSpotify

Tech Stack

Voice AI / Speech AI modelsAutomatic and streaming speech-to-textLLMsSpeech-understanding modelsDeveloper-facing APIs

Competitors

Deepgram
Microsoft Azure Speech Service
Google Cloud Speech-to-Text
Amazon Transcribe
OpenAI Whisper
Krisp

Key Investors

Accel, Insight Partners, Y Combinator, Nat Friedman