Dylan Fox

Founder and CEO AssemblyAI

Last Reviewed: September 18, 2026

Executive Summary

Dylan Fox is the founder and chief executive of AssemblyAI, a speech-to-text and audio intelligence company whose API lets developers transcribe, summarise, moderate and reason over audio without building or hosting speech models themselves. He started the company alone in 2017 out of Y Combinator’s Summer 2017 batch, having concluded while working on machine learning for Cisco’s collaboration products that the speech recognition services available to developers were years behind what modern deep learning could deliver. The bet has aged well: AssemblyAI now sits underneath a large share of the voice AI application layer, and by the time of its $50 million Series C in December 2023 the company reported training its models on roughly 1,250 times the data behind its first public model in 2019. Fox is unusual among AI founders in having come to machine learning from a business degree and self-taught programming rather than a research background.

Career Highlights

• Founded AssemblyAI in 2017 as a solo founder and went through Y Combinator’s Summer 2017 batch.
• Raised a $50 million Series C announced on 3 December 2023, led by Accel, taking total disclosed funding to $115 million.
• Built an investor roster spanning Accel, Insight Partners, Y Combinator, Daniel Gross, Nat Friedman and Keith Block’s Smith Point Capital.
• Shipped AssemblyAI’s first public speech model in 2019 and has since scaled training data roughly 1,250-fold.
• Previously a senior machine learning engineer at Cisco Systems in San Francisco, working on AI features for collaboration products.
• A regular voice in public discussion of speech AI, including Unite.AI’s founder interview series and voice AI industry podcasts.

Professional Journey

Fox studied business administration at George Washington University, concentrating on business economics and public policy — not a technical degree. He taught himself to program while in Washington DC, working through Python meetups in the city, and found himself drawn to algorithmic problems, which pulled him toward machine learning and natural language processing. That self-directed route into the field is the reason he tends to frame speech recognition as a developer-experience problem rather than purely a research one.

He moved to San Francisco and joined Cisco Systems as a senior software engineer working on machine learning for the company’s collaboration products, and led machine learning work there. Building AI features on top of audio, he ran into the state of commercially available speech recognition: the APIs developers could actually buy were dated, and the gap between them and what contemporary deep learning could do was widening. The rise of voice-first consumer products such as Amazon Alexa made the size of the coming demand obvious.

He resigned from Cisco and founded AssemblyAI in 2017 as a solo founder, applying to Y Combinator with a recorded video demonstrating the technology. He was invited to interview, and at YC’s office met Daniel Gross, formerly of Apple, who had examined speech recognition himself and recognised the problem Fox was describing. Gross became his first investor. AssemblyAI went through the Summer 2017 batch.

The company shipped its first publicly available model in 2019 and grew into an API platform covering transcription, speech understanding, summarisation and audio moderation. Funding accelerated sharply in the early 2020s: by the December 2023 Series C, Fox noted that roughly 90 percent of the company’s $115 million total had been raised in the preceding 22 months. Accel led both the Series A and the Series C, with Insight Partners, Y Combinator, Daniel Gross, Nat Friedman and Keith Block’s Smith Point Capital among the other backers. AssemblyAI operates remote-first, with a San Francisco base and staff distributed across several continents.

Education

George Washington University

Bachelor’s degree, Business Administration, with a focus on business economics and public policy