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Experience

EXIMBAY

Full-Stack Software Engineer

Cross-border payments

October 2023 – June 2026 · South Korea

Worked across mobile, web, and backend systems in a team of 1–2 developers. Supported EXIMPay+ (~30,000 MAU) while building and launching 2 new payment products, PG-ON and EXIMLink, using React Native, React, Node.js, and Spring Boot.

  • Migrated EXIMPay+’s separate native apps to React Native with zero downtime. Kept existing App Store identities for seamless updates, and rebuilt native integrations as Expo Modules.
  • Modernised the EXIMPay+ backend using Spring Boot. Designed a domain-based layered architecture, structuring core payment logic and state transitions into clean entities.
  • Strengthened security across mobile and backend systems. Implemented 6 mobile runtime checks based on OWASP guidance, and added MFA and strict session controls for admin and merchant accounts.
  • Cut iOS and Android build-and-upload time from about 90 minutes to under 30 minutes. Automated environment-specific builds and uploads to TestFlight and Google Play with Fastlane.
  • Built and launched EXIMLink to replace an outdated email-billing system. Delivered an end-to-end payment-link platform featuring merchant invoicing, public REST APIs, and automated webhook integration.
  • Developed PG-ON to bring web payments to existing payment terminals. Built a web application allowing merchants to process card and QR payments on existing hardware via a WebView bridge.
  • Introduced an AI-assisted development workflow with the team. Structured step-by-step reviews across planning, implementation, and testing, delivering features faster while maintaining high code quality.

Detion

Web & iOS Developer

Mobile identity startup

October 2021 – July 2023 · South Korea

Developed and maintained the DM Plus back office and public APIs, then moved into iOS development. Took over an existing iOS product and launched AIVI. Worked mainly with Express, React, and Swift.

  • Removed repeated 5-second polling using Server-Sent Events (SSE). Reduced unnecessary server traffic, allowing the web page to respond immediately once the mobile flow completed.
  • Built browser-based face matching and liveness checks. Implemented real-time facial tracking and expression analysis to verify user identity directly in the browser.
  • Replaced a paid OCR service with an on-device iOS passport scanner. Built a native module with ML Kit, implementing custom MRZ parsing and check-digit validation.
  • Launched AIVI, an AI image generation app for iOS. Implemented photo preprocessing, asynchronous image generation, and local image caching.

NGLE

QA Analyst

Software QA

May 2020 – October 2021 · South Korea

Performed QA for several client projects. Designed test cases from requirements, checked user flows, and reported defects.

  • Turned product specifications into structured test cases. Covered expected behaviours, edge cases, and regression scenarios across multiple client projects.
  • Identified flow inconsistencies and reproduced defects across user journeys. Documented precise conditions and reproduction steps to help developers investigate and resolve issues.

Education

Bachelor of Computer Science

Yong In University · Graduated February 2021