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Buildbox

YC F26

San Francisco, US · Founded 2026 · 2 employees · 5 known investors

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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 SoftwareSaaSAnalyticsAIUnited States of AmericaAmerica / Canada

Founders & leadership· Y Combinator alumni (F26)

Buildbox was founded in 2026 by Trishala Jain and Mark Nour.

TJTrishala Jain
Trishala JainCo-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 NourCo-FounderCo-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 · 5

Vela Partnerslisted by Vela PartnersSan Francisco · $100K – $500K
Y Combinatorlisted by Y CombinatorSan Francisco · $500K

How we know: the Y Combinator directory · Not right? Tell us

GaingelsreportedNew York · $200K – $500K

How we know: funding news · Not right? Tell us

London Venture PartnersreportedLondon

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Funding

SEC filings, press & company announcements

$20M disclosed across 1 of 2 rounds · 2021

Source: company announcements and press reports — follow each round's link for the claim.

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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 founded Buildbox?
Buildbox was founded by Trishala Jain, Mark Nour in 2026.
Who are Buildbox's investors?
Buildbox's investors include Raine, Vela Partners, Y Combinator, Gaingels, London Venture Partners.
How much funding has Buildbox raised?
Buildbox has disclosed $20M raised across 1 of its 2 known rounds.
Where is Buildbox headquartered?
Buildbox is headquartered in San Francisco, US.