David Youn

Backend Software Engineer

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Overview

Backend software engineer with 3 years of experience building and operating distributed, high-throughput systems at Amazon Web Services and healthcare technology companies.

Software engineering roles focused on backend systems, distributed services, API design, data processing, and production reliability.

Skills

Programming Languages

Java / Python / SQL / JavaScript / TypeScript / HTML

Frameworks & Tools

Spring Boot / Git / AWS CloudWatch / AWS Lambda / Amazon S3 / Ruby on Rails / Linux

Database Systems

MongoDB / MySQL / DynamoDB

Other

Object-Oriented Design / Distributed Systems / API Design / CI/CD / SDLC / E2E Testing

Experience

Software Engineer

ActX | Feb 2025 - Nov 2025 | Seattle, WA

  • Delivered 20+ production backend and full-stack features across a Java Spring backend, Ruby on Rails frontend, and MongoDB architecture supporting customer-facing healthcare applications.
  • Designed and implemented RESTful APIs integrating with third-party Electronic Health Record systems, enabling real-time clinical data exchange across multiple healthcare partners.
  • Led modernization of legacy Rails applications by upgrading Ruby 1.9 to 2.7, removing deprecated dependencies and reducing build warnings by 70%+.
  • Partnered with geneticists and domain experts to design backend workflow tools that automated manual bioinformatics processes.
  • Built Python-based data processing jobs to backfill and validate 50M+ patient records, improving data completeness and enabling downstream analytics.

Software Development Engineer

Amazon Web Services | Aug 2022 - Feb 2024 | Seattle, WA

  • Designed and shipped distributed REST APIs supporting cross-region replication for large-scale AWS services, improving resilience across multiple high-traffic regions.
  • Built and maintained real-time monitoring dashboards for APIs handling 100K+ requests per minute, enabling rapid anomaly detection and supporting a 99.9% availability SLA.
  • Improved system performance and reliability by optimizing Elasticsearch client usage, implementing retry logic, and addressing bottlenecks that reduced error rates under peak load.
  • Participated in a 24/7 on-call rotation for Tier 1 and Tier 2 services, performing root cause analysis, writing incident reports, and deploying production fixes.

Software Development Engineer Intern

Amazon Web Services | Jun 2021 - Sep 2021 | Remote

  • Developed a backend API to collect, store, and query historical user data in Amazon S3, improving data accessibility and reducing retrieval latency.
  • Authored internal technical documentation supporting onboarding and long-term maintainability.

Projects

Portfolio Agent Terminal

A browser-based terminal that lets recruiters ask questions about my projects, experience, and working style.

Shows practical agent deployment experience and makes my resume easier to explore interactively.

Next.js / OpenAI Agents SDK / Vercel

Education

University of California, San Diego

B.S. Computer Science | June 2022

GPA: 3.76/4.0