Available for opportunities

John
Scallan.

Software Engineer — Full-Stack Development
React, Node.js, JavaScript, AWS
Building Scalable Systems at Lockheed Martin

Location Greater Philadelphia
Focus Full-Stack & Frontend
Education Penn State University
John Scallan
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01 — About

Building what
users touch.

Software Engineer with production experience across the full stack—from React and Angular frontends to Node.js and Express APIs to PostgreSQL databases and AWS cloud infrastructure. At Lockheed Martin, I ship code that serves real users under real constraints: latency-sensitive APIs, high-throughput data pipelines, and mission-critical UI/UX.

I build systems that scale. I’ve cut API response times through request parallelism and query optimization, automated large-scale data ingestion with Lambda, S3, and SQS on Kubernetes, and eliminated developer bottlenecks by re-engineering container workflows. I write clean, testable code and I ship it through CI/CD.

Former Teaching Assistant for Data Structures at Penn State—I communicate complex ideas clearly and elevate the engineers around me. Open to opportunities where I can solve hard problems, own meaningful features, and grow as an engineer.

Technical Stack

Primary
JavaScript TypeScript React Node.js Express PostgreSQL
Infrastructure
AWS Docker Kubernetes Helm CI/CD
Also Work With
Angular Python C++ Electron MATLAB Git

02 — Experience

Where I’ve built.

Software Engineer
Lockheed Martin
Sep 2024 — Present
King of Prussia, PA · On-site · Full-time
  • Reduced API response latency by implementing request parallelism and PostgreSQL query optimization in a Node.js/Express.js backend serving internal and external users
  • Designed, prototyped, and shipped React interfaces across multiple product lines, translating customer requirements into production-ready UI components
  • Automated large-scale data ingestion with AWS Lambda, S3, and SQS; deployed and managed containerized processing workflows on Kubernetes with Helm
  • Enhanced mission-critical C++ image processing algorithms through object-oriented refactoring and memory management optimization
  • Eliminated redundant Docker image rebuilds by configuring symlinked Node.js modules, accelerating development cycles across the engineering team
  • Extended an Electron desktop application with IPC channels and custom worker processes; re-architected a blocking feature into a non-blocking workflow
  • Validated algorithmic outputs by analyzing Python and MATLAB codebases, ensuring feature correctness and cross-language consistency
  • Collaborated with customers, tech leads, and program management in Agile sprints to scope requirements and deliver on schedule
Teaching Assistant — Data Structures & Algorithms
Penn State University
Jan 2024 — May 2024
State College, PA · CMPSC 132
  • Mentored 200+ students in core CS concepts—linked lists, trees, graphs, hash tables, sorting, and algorithmic complexity—through office hours and 1-on-1 debugging sessions
  • Translated abstract data structure theory into clear, actionable guidance for students at varying skill levels
  • Supported course operations including exam proctoring, assignment grading, and recitation delivery
Software Engineer Intern
Lockheed Martin
May 2023 — Aug 2023
King of Prussia, PA
  • Built full-stack features on an Angular web application used to manage customer contracts, implementing frontend components and Node.js backend services
  • Designed and queried PostgreSQL schemas for user and contract data, ensuring data integrity and performant retrieval
  • Resolved production incidents through CI/CD pipeline debugging, maintaining service reliability and uptime
  • Authored and debugged unit tests across client and server codebases, improving code coverage and regression safety
Engineering Intern
Federal Reserve Bank of Philadelphia
Jun 2022 — Aug 2022
Philadelphia, PA
  • Designed and implemented an internal scheduling system with Microsoft PowerApps and Power Fx, enhancing workflow efficiency for employees
  • Coordinated with internal stakeholders to design wireframes and define application requirements
  • Automated large-scale data updates with a PowerShell script, processing millions of employee records across servers in an SQL database

03 — Beyond the Code

What I do offline.

♟

Chess

Avid online chess player. To me it feels like a realm where there is always room for improvement. I enjoy watching chess content on youtube as well.

💪

Calisthenics & Lifting

Consistent training with bodyweight movements and weights, including handstands and levers. The discipline required for this hobby has significantly contributed to what defines me today.

💻

Side Projects

Currently building BreezeChess—an online chess website. Side projects are where I experiment with new tech and own every decision from UI to deployment.

🎸

Acoustic Guitar

Playing guitar is how I unplug or even just relieve the boredom. Although I wouldn't call myself particlarly talented at it, I enjoy learning new songs and chords.

04 — Contact

Let’s connect.

Open to software engineering opportunities across industries. Let’s talk about what I can build for your team.

LinkedIn GitHub Email