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Patrick Kearney

Hi, I'm

Patrick Kearney

Software Engineer · 4+ years of experience

Software engineer specializing in payments and e-commerce systems. I modernize legacy services, build cloud-native APIs on AWS, and ship well-tested code in Java and TypeScript.

London, Ontario, Canada · Open to remote and hybrid roles

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About

I've spent my career on payments and commerce teams at CARFAX, where reliability matters: when checkout breaks, revenue stops. My work has ranged from upgrading long-lived Java services and replacing legacy payment SDKs with modern APIs, to designing new tax and commerce services from the ground up.

I care about leaving systems better than I found them: safer secret handling, smaller and simpler services, and tests that make change cheap. I use AI tools like Claude day to day to move faster on boilerplate and test coverage, so more of my time goes into design and review. This site's repo is an example of that workflow.

Experience

  1. Software Engineer · CARFAX

    · London, ON

    • Helped plan, design and build a new payments and tax platform on the open-source MedusaJS commerce framework, using its built-in data model to speed up delivery.
    • Designed a Java 17 Tax API that lets internal teams quote and record sales tax through one shared service.
    • Java 17
    • TypeScript
    • MedusaJS
    • Vertex

  2. Associate Software Engineer · CARFAX

    · London, ON

    • Maintained integrations with multiple payment providers for the consumer purchase flow.
    • Upgraded payment services from Java 8 to Java 17 and replaced a 20-year-old payment-gateway SDK with direct, API-driven integrations.
    • Rewrote a legacy Java 8 application as a TypeScript AWS Lambda and cut traffic over at the API gateway with zero downtime. Added automatic 30-day rotation of its encryption key.
    • Built a Google Pay proof of concept on the checkout page and ran an A/B test to measure its value. The data showed it wasn't worth the added complexity, so we chose not to roll it out.
    • Java
    • TypeScript
    • AWS Lambda
    • AWS Secrets Manager

Education

  • Computer Programming Analyst · Fanshawe College

    2018 – 2021 · London, ON

    • President's Honour Roll

Skills

Languages

  • Java
  • TypeScript
  • JavaScript
  • SQL
  • C++

Backend & APIs

  • Spring Boot
  • Node.js
  • Express
  • MedusaJS
  • REST
  • OpenAPI / Swagger
  • Zod
  • Jackson
  • Lombok

Frontend

  • React
  • Next.js
  • Tailwind CSS

Cloud (AWS)

  • Lambda
  • API Gateway
  • ECS / Fargate
  • RDS / Aurora
  • SQS
  • S3
  • EventBridge
  • SES
  • EC2
  • IAM
  • KMS
  • Secrets Manager
  • CloudWatch

Infrastructure & CI/CD

  • AWS CDK
  • Terraform
  • Serverless Framework
  • Docker
  • Docker Compose
  • Gloo Gateway
  • GitLab CI
  • Jenkins

Databases

  • PostgreSQL
  • MySQL
  • Redis
  • DynamoDB
  • MongoDB

Payments & Commerce

  • PayPal
  • Amazon Pay
  • Google Pay
  • Chase Orbital
  • Vertex (tax)
  • PCI DSS (SAQ A & D)
  • Optimizely A/B testing

Testing

  • JUnit
  • Mockito
  • Jest
  • Vitest
  • React Testing Library
  • Playwright

Observability

  • New Relic
  • Grafana
  • PagerDuty
  • CloudWatch

Build & Dev Tools

  • Gradle
  • Maven
  • npm
  • Yarn
  • Prettier
  • IntelliJ IDEA
  • VS Code
  • Postman
  • Bruno
  • Linux
  • Bash / Zsh

Collaboration

  • Git
  • GitHub
  • GitLab
  • Bitbucket
  • Jira
  • Confluence
  • Agile

AI-Assisted Development

  • Claude Code
  • GitHub Copilot

Currently Learning

  • Python
  • Go
  • Rust

Projects

This Website

A statically exported Next.js resume site with typed content, unit tests, end-to-end tests, and automated accessibility checks.

  • Next.js
  • TypeScript
  • Tailwind CSS
  • Vitest
  • Playwright

Contact

I'm open to new opportunities. The best way to reach me is by email.