Jun

Work Experience

March. 2024 ~ Now

Tax Refund Service Maintenance and Development (Z ENTERPRISE)

Frontend Engineer

Improved operational environment by automating Continuous Integration tests using Github Action and Husky.
Enhanced automated deployment systems utilizing Lambda and Event Bridge.
Established monitoring systems with Datadog Error Alert and Real User Monitoring.
Implemented a non-deployment service check page using Edge Config and Middleware.
Conducted A/B testing to optimize service features.
Set up an independent testing environment increasing Test Coverage from 0% to 30%.
Enabled API-independent environment through GraphQL Mocking and transitioned from MSW to Cypress Intercept.
Minimized flaky tests to improve reliability.
Enhanced Core Web Vitals metrics, focusing on LCP improvement through Image and Font Optimization.
Upgraded legacy design systems and maintained Xstate.
Managed large-scale traffic promotions by separating Service FE and Promotion FE servers.
Developed a waiting logic for managing DB connections during high traffic.

Next.jsRelayGithub ActionAWS LambdaEvent BridgeDatadogEdge ConfigMiddlewareGraphQLCypressImage OptimizationFont OptimizationXstate

March. 2023 ~ Now

B2B Saas API Platform (Asleep)

Backend Engineer

Developed Dashboard APIs offering metrics like DAU, MAU, and Stickiness, resolving cross-domain service calls via BFF implementation.
Introduced consistent code conventions through DDD adoption (Hexagonal Architecture, Layered Architecture), along with comprehensive Integration and Unit testing.
Automated Cloud Infra management using AWS CDK and established a MonoRepo.
Provided Swagger Docs and standardized ubiquitous language.
Implemented automated deletion of information for approximately 100,000 departed members using Jenkins for batch automation and monitoring.
Created an API Usage Alert service automating usage checks and sending warning emails using Jenkins and AWS SES.
Configured email templates and set up Slack notifications for health checks.
Developed an admin panel managing contracts, emails, and usage, enhancing architecture considering development effort by utilizing GraphQL for communication among MSA services.
Implemented CI/CD pipelines using Github Action, integrated RBAC for user authorization via Cognito, and established offset-based Pagination, coupled with API Logging using Datadog.
Expedited development in Developer Mode by shortening sleep analysis feature development from a minimum of 20 minutes to 2 minutes by optimizing data storage speed without persistence using Redis.

FastAPIPythonGraphqlAWSMySQL

Nov. 2022 ~ Feb. 2023

B2B Saas Dashboard (Asleep)

Frontend Engineer

Next.jsTypescriptTailwindCSSVercelAWSGraphql

March. 2022 ~ Nov. 2022

B2C application for managing sleep habits (Asleep)

Frontend Engineer

Developing a web view for sleep habit management application reports
Enhancing Carousel performance
Implementing Virtual Slides
Incorporating multilingual support
Shifting Remote Config to SSR
Transitioning libraries: CRA to Next.js, AWS Amplify to Vercel, Styled-components to Styletron
Managing server state
Introducing React-query and Ky
Testing libraries: Cypress for E2E Testing, Testing Library for Component Testing
Establishing a Monorepo using Nx.

Next.jsTypescriptStyletronRecoilCypressStorybook

Nov. 2020 ~ March. 2023

Developed and maintained the official website for A-Sleep (Asleep)

Frontend Engineer

Applying SSR, SSG, and ISR (incremental static regeneration)
Minimizing API calls for optimal performance
Improving initial loading speed
Utilizing Google Spreadsheet API
Cost-saving through Admin and API development strategies
Implementing Atomic Design patterns for component reusability
Conducting SEO operations such as Sitemap, Favicon, Open Graph protocol, and PWA integration
Implementing Scroll, Gesture, and layout animations using React-framer.

Next.jsTypescriptTailwindCSSAmplify

April. 2020 ~ July. 2021

Sleep analysis application based on AI analysis of sound data (Asleep)

Android Engineer