Software Engineer Backend Developer

DAEHAN CHOI

703-***-**** ad5uak@r.postjobfree.com

US Green Card holder

SUMMARY

Motivated Backend Developer with more than three years of experience. Specializing in Kotlin, Java and Spring with proficiency in JavaScript. Expertise with Linux and a keen interest in large-scale service architectures and network solutions. Team-oriented professional, who thrives in collaborative environments utilizing positive team dynamics and continuous learning. Eager to apply my skills and enthusiasm for technology in development and system design. Constantly seeking new methods and exploring new ways to innovate and improve. A bilingual professional fluent in both Korean and English, who brings valuable communication skills and cultural awareness to global teams. TECHNICAL SKILLS

- Main Languages: Kotlin, Java, SQL

- Sub Languages: Javascript, Python, Flutter

- Frameworks: Spring, Spring Data, Hibernate, JPA, QueryDsl, MyBatis

- Databases: Postgres

- Infrastructures: Docker, Kubernetes

- OS: Mac, Windows, Basic Linux

- APIs & Protocols: Rest API, GraphQL, gRPC

- Version Control: Git

EXPERIENCE

Backend Developer Onion Mobility Seoul, Republic of South Korea March 2022 – Present

Innovative Architecture: Developed a user-friendly wallet service (proprietary server interface), simplifying transactions by integrating seamlessly with the system and improving user experience.

Quality Assurance: Achieved and maintained core and systems services and wallet for transportation fleet service systems, utilizing an IDE (Integrated Development Environment) for test coverage, ensuring high standards of error minimization in software quality.

Data Analysis and Optimization: Analyzed packet data with Pandas (framework/library) and adopted Apollo Federation for GraphQL, simplifying the architecture.

Data Type Safety Improvement: Enhanced system robustness by applying advanced type safety mechanisms, resulting in reduced errors and improved code reliability.

Google Sheet Data Migration: Effectively spearheaded the migration of data from Google Sheets to a database using Python, enhancing system compatibility and data management efficiency.

Retool Migration: Independently transitioned the admin webpage to the no-code Retool platform, streamlining the interface and backend, reducing maintenance needs, and enhancing system efficiency.

Backend Developer/Project Leader Try Catch Seongnam, Republic of South Korea April 2021 – February 2022

API Enhancement and Bot Data Management: Introduced Swagger3 (API Spec Building Tool) for streamlined testing and system reliability, created an efficient system for bot information export/import in JSON.

Leadership and Service Launch: Led project collaborations ensuring team integration and project execution smoothly and improved development experience by implementing Field Cryptor.

Multi-Tenancy Design and Developer Experience: Devised a JPA-based multi-tenancy structure, reducing maintenance for more than 60 applications. Junior Solution Engineer/Project Manager ePapyrus Seongnam, Republic of South Korea September 2020 – April 2021

Customization, Enhancement and Upgrade Development: Identified and provided a strategic solution for converting 1.5 million HTML files to PDFs, effectively guiding the core team in resolving a complex technical challenge and optimizing software performance.

Project Coordination: Effectively managed project timelines and client interactions, ensuring projects were completed smoothly and on schedule.

Enhanced System Reliability: Transitioned from a map-based to a class-based JSON structure for HTTP requests, significantly improving type safety and system stability in our Spring applications.

Backend Developer Remarkable Soft Seoul, Republic of South Korea May 2020 – September 2020

Code Integration: Refactored repeated code across various pages and strategically selected package management, enhancing project efficiency.

Traffic Reduction: Implemented EhCache (library for Java) in the ranking system, streamlined network traffic and reduced overall network load.

Tech Stack Upgrade: Modernized the tech stack by integrating advanced technologies such as ES6 and Lombok.

EDUCATION

B.S. Degree, Korea National Open University, Suwon Republic of South Korea, 2023

Focused on computer science principles, software development, algorithm design and system analysis

CERTIFICATIONS

- SQL Developer, Korea Data Agency

- Engineering Information Processing, Human Resources Development Service of Korea LANGUAGES

English (Advanced), Korean (native)

PROJECTS

YouTube Quality Shortcut - Chrome Extension

Feb 2024 - Current (Maintenance & Minor Improvements) https://chromewebstore.google.com/detail/youtube-quality-shortcut/idcemhhjdleodchiihagkfehahofmibc

Contact this candidate