Fundraising Fox

Buildbox

YC S26

San Francisco, US · Founded 2026 · 2 employees · 3 known investors

heybuildbox.com ↗

Buildbox is a platform that detects failed user journeys in AI agents that pass their evals but still fail to help users complete tasks, ranking these failures by business impact. It ties agent failures to outcomes and tests alternative agent behaviors against the same customer task before release.

AI & Machine LearningData & InfrastructureDeveloper ToolsEnterprise SoftwareSaaSArtificial IntelligenceAnalyticsUnited States of AmericaAmerica / Canada

Founders & leadership· Y Combinator alumni (S26)

TJTrishala Jain
Trishala Jainin𝕏Co-FounderCo-founder of Buildbox, which detects and ranks failed user journeys in AI agents and tests alternative agent behaviors before release. She previously worked at Google Labs, MongoDB, and AppDynamics, and holds a UC Berkeley M.E.T. degree in EECS and Business.
MNMark Nour
Mark Nourin𝕏FounderCo-founder of Buildbox, which builds a platform for detecting and ranking failed user journeys in AI agents. He previously worked at Netflix and Google Cloud and studied computer science at Berkeley.

Investors · 3

Y CombinatorSan Francisco · $500K
GaingelsreportedNew York · $200K – $500K
London Venture PartnersreportedLondon

In the news

Buildbox: Agent analytics for real user outcomesycombinator.com · Aug 2026AppOnboard raises $20m for Buildbox engine | GamesIndustry.bizgamesindustry.biz · Feb 2021Buildbox raises US$20mil so anyone can make the next ‘Pokemon Go’thestar.com.my · Jan 2021Roblox to Delay Listing for Second Time; Buildbox Raises USD$20m - TheGamingEconomy.comthegamingeconomy.exchangewire.com · Jan 2021Buildbox Raises $20 Million so Anyone Can Make the Next Pokemon Go | Financial Postfinancialpost.com · Jan 2021AppOnboard acquires Buildbox - Buildbox | Game Maker | Video Game Softwarebuildbox.com · Jun 2019Buildbox raises US$20mil so anyone can make the next ‘Pokemon Go’ | Nestianews.nestia.com

Frequently asked questions

What does Buildbox do?
Buildbox is a platform that detects failed user journeys in AI agents that pass their evals but still fail to help users complete tasks, ranking these failures by business impact. It ties agent failures to outcomes and tests alternative agent behaviors against the same customer task before release.
Who are Buildbox's investors?
Buildbox's investors include Y Combinator, Gaingels, London Venture Partners.
Where is Buildbox headquartered?
Buildbox is headquartered in San Francisco, US.