Jaeho Lee

Tax invoice feature frontend development (2024.06 — 2024.12)

• Built the tax invoice list and invoice-style authoring UI for a financial B2B expansion project.
• Used ts-pattern to describe complex combinations of tax invoice issuance states and revision reasons as declaratively as possible, reducing repeated branching.
• Used Valibot to define form validation declaratively so constraints were easy to understand.

Led the renewal of the Partner Settlement product and development of the payout-agent feature (2024.01 — 2024.05)

• Joined a newly formed B2B team for a new business model and experienced a 0-to-1 product build.
• Integrated the Key#Biz digital certificate solution to satisfy the legal basis for settlement payouts. Because the solution did not fit a modern SPA well, wrapped it with an iframe abstraction and improved usability.
• Built TanStack Table-based settlement tables, then established shared abstractions and file naming conventions as similar tables and pages continued to grow.

Design system cleanup (2025.05 — 2025.09)

• Reviewed a neglected design system after significant team turnover and proposed a new shadcn/ui-based direction, contributing to a gradual migration over a long period.
• Proposed shadcn/ui because it fit the admin-style look and feel, had the required components, and matched my experience building Tailwind-based design systems.
• Pushed for Figma cleanup so screens were reorganized around components. As a result, frontend engineers could implement from component properties more easily, and tools such as Figma MCP became more useful for productivity. The overall UI also became more consistent and polished.

Built and launched Portone Analytics (2023.07 — 2023.10)

• Built the overall UI, chart integrations, and GraphQL API integration for the successful launch of Portone Analytics.

Frontend productivity and UX improvements (2025.01 — 2025.09)

• Designed UX for Vercel version skew so users could update naturally without hitting errors, using update toasts, reloads on route transitions when an update was required, and refresh handling for vite:preloadError.
• Reduced the initial downloaded asset size to one-third through React Router-based bundle splitting.
• Built a Playwright screenshot testing tool to compare screens against production, detect broken UI, and review all implemented screens.

Built the international farmer app Farmmy (2022.11 — 2023.02)

• Introduced Formula design components, handled troubleshooting, and built the peer-to-peer marketplace feature.
• Handled localization key sync with Lokalise and implemented SSR support.

Built the in-house design system Formula (2022.06 — 2023.02)

• Designed a company-wide design system with designers for headquarters and three subsidiaries, based on Material Design.
• Wrote detailed style-dictionary transforms and Figma Tokens sync scripts.
• Built TypeScript and vanilla-extract components, added ReScript bindings, and wrote developer guides.
• Reference: https://github.com/green-labs/formula-design-system

Built the farmer super-app Farmmorning (2021.11 — 2023.02)

• Implemented features such as market expansion and farming journal flows, contributing to user growth.
• Built feature onboarding screens, user input forms, and review screens using Relay and React Hook Form.
• Migrated an S3-hosted CSR app to Next.js and Tailwind and deployed it to Vercel after SEO needs emerged.
• As frontend team lead, drove technical decisions such as adopting Next.js and feature flags, handled troubleshooting, and planned open-sourcing parts of the internal codebase.

Tech: React, Next.js, ReScript, TypeScript, Relay

Led development of the Nexclipper Prometheus web console (2021.01 — 2021.11)

• Reworked an outsourced redux-saga legacy project into a more maintainable React Query and Jotai-based structure.
• Introduced a Yarn Berry monorepo to support variable customer-specific UIs.
• Built additional console prototypes and shared UI components based on Ant Design.
• Trained junior engineers, reviewed code, and handled troubleshooting.

Tech: React, React Query, TypeScript, Jotai