DisputeNinja

Overview

DisputeNinja was a San Francisco-based fintech startup founded in 2023 by Max Wu and Bowen Xue. ^[1] Accepted into Y Combinator's Summer 2023 batch, the company built AI agents that automated chargeback evidence collection and dispute response drafting, targeting software and AI startups as its primary customer segment. ^[2] The two-person team operated out of San Francisco with no disclosed external hires and no publicly announced revenue milestones.

DisputeNinja's core value proposition was rendered structurally non-viable by its primary infrastructure dependency: Stripe, the dominant payment processor for its target customers. In June 2025, Stripe introduced a $15 counter fee for merchants who manually contest chargebacks using third-party tools — waived only for users of Stripe's own native product. ^[3] Five months later, Stripe launched Smart Disputes, an AI-powered chargeback automation tool trained on $1.4 trillion in annual payments volume, directly replicating DisputeNinja's product. ^[4]

No formal shutdown announcement has been published. The DisputeNinja website remains live, and both founders' LinkedIn profiles still list the company as active. ^[5] The absence of any follow-on funding, press coverage, or community discussion — combined with Stripe's platform moves — points to a company that quietly became non-viable rather than one that closed with fanfare.

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Founding Story

Max Wu and Bowen Xue came to chargeback automation through direct, painful experience. Before founding DisputeNinja, both worked at startups operating in the NFT and cryptocurrency space — a sector notorious for payment fraud. ^[6] At those companies, the founders discovered that fraudulent NFT sellers accounted for roughly 90% of fraud cases, yet the existing fraud-prevention vendors they relied on had no meaningful solution for the problem. ^[7] The vendors were built for traditional e-commerce patterns, not the fast-moving, pseudonymous dynamics of crypto marketplaces.

Wu graduated from UCLA, while Xue studied at the University of Waterloo — Waterloo being a well-established pipeline for technical founders in North America. ^{[8] [9]} Xue had previously worked as a software engineer at Paper, an education technology company, before co-founding the company. ^[10] Neither founder had a background in payments or financial services specifically — their expertise was in building software products and fighting fraud operationally, not in the regulatory or banking infrastructure that underlies chargeback processes.

The founding insight was experiential rather than analytical: the founders had lived the problem of inadequate fraud tooling and believed they could build something better. This is a common and often reliable origin story for B2B software companies — the founders are their own first customer. The specific pivot from general fraud prevention to chargeback automation appears to have been a product focus decision made around the time of YC application, though the precise timing is not documented publicly.

What makes the founding story structurally unusual is that Wu and Xue simultaneously launched two companies under the same YC batch: DisputeNinja (chargeback automation for software startups) and Trench (open-source fraud prevention for marketplaces). ^[11] Both were accepted into S23, which consisted of 247 companies selected from over 24,000 applications. ^[12] Whether this dual structure reflected a deliberate portfolio strategy, a hedge against product-market fit uncertainty, or simply two complementary tools within a single fraud-tooling thesis is not documented. YC's public announcement in August 2023 focused on Trench, describing it as an open-source, self-hosted fraud prevention platform for marketplaces — with DisputeNinja's chargeback product operating in parallel. ^[13]