Curtis Fenner Tokyo, Japan

Experience

Givery Engineer, "Track Test" & "Common Systems" teams

Tokyo, JP. Jan 2023 – current

• Track Test Team dev. lead (2025–): estimated, designed, and refined plans for long-term projects
• Led architecture design, technology choice and modernization, and implementation of new product
  • Introduced new Zod-based wrappers to improve type-safety & eliminate validation boilerplate
  • Designed and implemented precise permission engine to make permissions & role checks standardized, flexible, and obviously correct
• Redesigned slow SQL queries to eliminate load and change slow-loading pages to instantly loading ones
• Refactored and documented internal scoring and submission logic to improve auditability, squash bugs, and increase extensibility
• Scala (Play), TypeScript (NestJS + Kysely) with Postgresql (backends)
• TypeScript (React) (frontend)
• AWS (ECS, Lambda, Rekognition, S3)

PayPay Backend Engineer, "Online" team

Remote, Jun '21 – Apr '22

Tokyo, JP. Apr 2022 – Jan 2023

• Backend engineer on the Online team, which external APIs for accepting PayPay payments online
• Designed, documented, and implemented new APIs used by merchants to accept PayPay payments
• Designed and lead a new microservice, using requirements from Product Managers and other teams
• Kotlin & Java (Spring Boot) with MySQL (backend)
• AWS (EC2, KMS)

Square Software Engineer, "Orders API" team

Atlanta, GA. Aug 2018 – Dec 2020

• Backend engineer on the Orders API team, which operates both a public REST API and internal POS API
• Refactored, tested, thoroughly documented, and simplified complex validation, transaction calculation, and public API versioning logic
• Java, MySQL, and Protobuf (strongly consistent API server)
• TypeScript (React) (internal web UI)

Education

University of Michigan: Computer Science B.S.E, 4.0 GPA

Ann Arbor, MI. 2014 – 2018

• Selected Coursework: Distributed Systems (W2017), Grad. Programming Languages (F2017)
• Teaching assistant for Distributed Systems using Golang (F2017)
• World Finalist in 2017 ACM International Collegiate Programming Contest (ICPC)
• Japanese Language I + II

I had 3 software engineering internships shipping real production code before graduating from university:

• Qualtrics
  Seattle, WA. Summer 2017
  • Scala and Elasticsearch (customer report generation)
  • Redesigned statistical weighting formulas to fix error independently discovered
• Qumulo
  Seattle, WA. Summer 2016
  • C (filesystem server) and Python (test automation and code generation)
  • Eliminated lock contention in a multithreaded cache to reduce file operation latency
• Square
  San Francisco, CA. Summer 2015
  • Node.JS and Go (microservice backends)
  • Optimized and refactored public API server to halve average response time

Japanese Language Proficiency Test N3 (JLPT/日本語能力試験)

Tokyo – July 2024

Selected Projects

Tokyo Rail-Transit Isochrone

github.com/CurtisFenner/tokyo-transit-iso

• Implemented routing algorithm and region geometry rendering algorithm on real transit schedule data
• TypeScript, MapLibre GL JS

Shiru Programming Language & Compiler

github.com/CurtisFenner/shiru-ts

• Designed and implemented a toy programming language, compiler, and assertion verifier, including a PEG parser, a type-checker, a simple SMT solver, and a JavaScript code generator.
• TypeScript