Executive Spotlight: Hilary Mason, Co-Founder and CEO of Hidden Door (2027)
Hilary Mason is the co-founder and CEO of Hidden Door, a New York studio that builds story worlds people can play, read and watch, working with the rights holders of existing fiction. She co-founded the company with Matt Brandwein.
Before Hidden Door she founded the applied machine learning research firm Fast Forward Labs, which Cloudera acquired in 2017, and earlier she was chief scientist at bitly.
This page uses public professional information only.
Current role and company
Hidden Door's about page lists Mason as Co-founder and CEO, and her own projects page describes the same role. The company says it was founded on February 18, 2020. Its press page calls it a transmedia studio building immersive fan experiences in fictional worlds.
- TitleCo-founder and CEO, Hidden Door (per the company's about page).
- Co-founderMatt Brandwein, listed as co-founder, Product.
- Investors namedMakers Fund, Northzone, Betaworks, Brooklyn Bridge Ventures and Homebrew, plus Dan Sturman and Joshua Schacter. No amounts or round dates are published.
Career path
- hackNY, 2010. Co-founded the nonprofit that places student engineers at New York City startups.
- bitly, around 2011 and 2012. Press items on her own site from those years describe her as bitly's chief scientist.
- Fast Forward Labs, 2014 to 2017. Founded the applied machine learning research company in 2014. Cloudera acquired it in 2017.
- Cloudera, from 2017. Served as VP of Research and then General Manager of Machine Learning.
- Hidden Door, 2020 onward. Co-founded the company that turns existing stories into playable worlds. A 2022 press item on her site marks the launch of its AI game platform.
What she is known for
- Applied machine learning. Her research firm focused on turning machine learning research into practical products before Cloudera bought it.
- Books and community. She co-authored Data Driven: Creating a Data Culture (O'Reilly, 2014) with DJ Patil and Ethics and Data Science (O'Reilly, 2018) with Mike Loukides and DJ Patil, and co-hosted the New York data conference DataGotham from 2012.
- Recognition. Her site lists Fortune's 40 Under 40 in 2011 and Fast Company's 100 Most Creative People in Business in 2013.
- Narrative AI. Hidden Door describes a world model that stores characters, rules and canon, and a story engine that checks player actions against that canon, with rights holders deciding what is canon.
Leadership style and philosophy
The pages we could read give no first-person interview text, so we do not quote her. Hidden Door's own site frames the approach: rights holders control what is canon and what can change, and its team describes itself as creative technologists with more than a decade of experience building machine learning products.
Key numbers
All figures below are reported by Hidden Door on its own site, as read on October 31, 2026. The pages give no earlier dates for the model figures.
- FoundedFebruary 18, 2020 (company-reported).
- Specialized narrative tasksAbout 100 tasks handled by its models (company-reported).
- Model size claimA tuned 1.7B-parameter model beat a 120B general model on one core task (company-reported).
- Team listedSix people on the about page, based in New York City.
What to watch next
Worth tracking: which rights holders sign on to Hidden Door worlds, new formats beyond games such as microdramas and audio series, and any new funding the company announces.
Questions people ask
Who is Hilary Mason?
She is the co-founder and CEO of Hidden Door and the founder of Fast Forward Labs, the machine learning research company Cloudera acquired in 2017.
What is Hilary Mason's current role?
Co-founder and CEO of Hidden Door, per the company's about page and her own site.
What does Hidden Door do?
It builds story worlds that audiences can play, read and watch, in partnership with rights holders, using a world model and a story engine.
What did she do before Hidden Door?
She founded Fast Forward Labs in 2014, then led machine learning at Cloudera after its 2017 acquisition. Earlier she was bitly's chief scientist.
Who invested in Hidden Door?
The company names Makers Fund, Northzone, Betaworks, Brooklyn Bridge Ventures and Homebrew, plus Dan Sturman and Joshua Schacter. It does not publish amounts.
Sources
- Hidden Door: About · Current title, co-founder, team, investors
- Hidden Door: Home · Product description and company-reported model figures
- Hidden Door: Press · Founding date and company description
- Hilary Mason: Projects and press · Career dates, books, recognition
- Wikimedia Commons: Hilary Mason at SXSW March 2024 · Hero photo, CC BY-SA 4.0
Facts were read from the linked pages on October 31, 2026. Some pages were read through a fetch tool that returns summaries, so confirm details on the original page. The hero photo is by Kevin Payravi under CC BY-SA 4.0, centered on a card. This page covers public professional information only.
Top photo: Kevin Payravi, CC BY-SA 4.0 (Wikimedia Commons)