Product Growth
Lifecycle and conversion work that connects user needs, pricing, onboarding, and post-launch measurement.
Senior Fintech Engineer
Hello, my name is
Yudai Yaguchi
Product-minded Fintech Engineer
I build and operate fintech systems at the intersection of payments, risk/compliance, product growth, and operations tooling. My work turns ambiguous customer and internal workflows into reliable, monitored systems that keep improving after launch.
6+ yrspayments, risk, and product systems
Risk + ComplianceKYC, OFAC, disputes, and monitoring
Product + Opscustomer UX and internal tools
Atlas impact
Fintech work across product, risk, money movement, and operations.
The common thread is owning ambiguous fintech problems end-to-end: define the customer or operations pain, ship the system, monitor the rollout, and keep improving the numbers after launch.
- GrowthProduct initiatives across onboarding, conversion, retention, and lifecycle communication
- PlatformsInternal tools and workflows that help operations teams move with better visibility
- Core flowsWork spanning product UX, risk controls, money movement, support, and analytics
Risk and Reliability
Regulated workflows, monitoring, review tools, and operational controls for sensitive fintech surfaces.
Money Movement
Payment and transaction experiences designed with backend reliability, observability, and supportability in mind.
Operations Platforms
Internal workflows, support tooling, dashboards, and automations that make teams faster and safer.
Sensitive implementation details and private metrics are summarized at a high level here; the focus is scope, ownership, and engineering judgment.
Experience
Education
Engineering writing, published beyond this site.
Articles I've authored on company and industry engineering blogs.
Why Financial Products Need Explainable States (opens in a new tab)
Why modeling a financial product's status as explicit, explainable states improves reliability, support, and user trust.
Fintech Internal Tools Are Risk Systems: How to Build Them Securely (opens in a new tab)
Explains how fintech internal tools should be treated as risk systems, with action-level permissions, approval workflows, audit trails, request IDs, and idempotent execution for sensitive operations.
Latest Blog
View all postsNotes on engineering, lessons learned, and ideas explored in public.
Coming soon...
Community Leadership
Building and leading an AI engineering community in the Bay Area.
Founder & Organizer — Bay Area AI Study Group
Beyond my fintech work, I founded and run the Bay Area AI Study Group: a monthly meetup and a self-built platform where engineers share projects, articles, and lessons learned.
- MonthlyIn-person AI meetups in the Bay Area, organized and hosted end-to-end.
- Self-builtCommunity platform built with Next.js and Firebase for sharing projects and Q&A.
- JTPARun in partnership with JTPA, a nonprofit supporting Japan–US tech talent.
Organizer & Host
Plan and run the monthly meetup end-to-end: agenda, speakers, venue, and check-in.
Platform Builder
Designed and built bayarea-ai.com from scratch with Next.js and Firebase.
Curating Member Work
Review and showcase member projects, articles, and tips submitted to the community hub.
Japan–US Bridge
Connect Japanese-speaking engineers in the Bay Area around AI, alongside JTPA.
Visit the community
The community runs in Japanese for Bay Area engineers; the platform and event information are also available in English.
Useful Tools
Production-ready utilities built to solve real-world day-to-day problems.
SettliSettlement Tool
Smart group payment settlement. Automatically finds the optimal transfer plan for complex bill splits.
Optimized SettlementWeighted SplitQR Share
KaimonoShopping List
Smart shopping lists with budgets, categories, sharing, and recurring item reminders.
Budget TrackingRecurring ItemsQR Share
KuizuQuiz Tool
Multiplayer quiz platform with 400+ questions, daily challenges, custom quizzes, and live scoreboards.
Multiplayer RoomsDaily ChallengesCustom Quizzes
MD PreviewMarkdown Viewer
Drag & drop or paste markdown files for instant full-screen preview with GitHub Flavored Markdown support.
Drag & DropClipboard PasteGFM Support
Railway PlannerFictional Rail Tool
Plan fictional railways from national trunk lines down to zoomed station layouts for all 47 prefectures.
All prefecturesService patternsCost simulation
TodoAI Task Manager
Extract tasks from screenshots or text with AI. Manage your todo list with smart input.
Screenshot to tasksText extractionAI-powered
スコアトラッカーScore Tracker
麻雀の素点、ゴルフ、ボドゲ会など — 日付ごとの最終点を記録して累計を追跡。コードで友達と共有できます。
日次スコア記録累計の自動集計コード共有
Coming Soon...
More practical tools are on the way.
Project Case Studies
Selected builds with context on the product problem, technical choices, and delivered outcome.
- All
- Web App
- Mobile
- AI/ML
- Console
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Study Lab
Articles and interactive CS labs for learning by reading, running, and checking understanding.
Interactive Games
Playable experiments focused on UX, performance, and game logic design.
Senior Fintech Engineer
Yudai Yaguchi
Biography
Hi, I'm Yudai — a senior software engineer based in San Francisco with 6+ years building production fintech systems across payments, risk, compliance, growth, and operations. At Atlas and PayPal, I have owned payment integrations, KYC/OFAC and dispute workflows, support and risk tooling, monitoring, and customer-facing activation and retention experiences. I am strongest when the problem is cross-functional: turn unclear business goals into a shippable system, coordinate rollout details, instrument the results, and keep improving the customer and operations experience. Outside of work, I lead an AI meetup community for engineers and keep exploring how machine learning fits into everyday products. I'm pursuing an MS in Computer Science at Westcliff University while looking for the next role that blends deep engineering with product ownership.
- 28 years
- San Francisco
- uwyudai@gmail.com
- English, Japanese