Joseph Karl Crisostomo

joseph.dev.ph@gmail.com · +63 960 4431 908 · Manila, PH (UTC+8) · Portfolio Site

Summary

Technology-agnostic full-stack engineer who picks up new tools fast and ships across multiple projects. Comfortable jumping between Rails, Node/TypeScript, Python/Django, and AWS, and handling whatever task comes up next.

Skills

• Full-Stack: Ruby on Rails, Hotwire (Turbo/Stimulus), Node.js, TypeScript, JavaScript, Python, Django, React
• Frontend: Next.js, Tailwind CSS, Leaflet, HTML, CSS
• Backend & Data: REST integrations, WebSocket/SSE, PostgreSQL, RDS, Redis (ElastiCache), Amazon MQ, query optimization
• Infra & DevOps: AWS (EC2, S3, EKS, CloudFormation, CodeBuild, ECR, CloudWatch), Docker, Kubernetes, Kamal, CI/CD
• Quality & Tooling: Automated testing (unit/controller), Grafana K6 load testing, Git

Experience

Backend Developer — Department of Science and Technology, Advanced Science and Technology Institute

On-site · Feb 2024 – March 2026

• Worked across a broad mix of tasks — backend features, infrastructure, testing, and database tuning.
• Built and managed containerized (Docker) services across on-premise Ubuntu servers and AWS, orchestrated with Elastic Kubernetes Service (EKS).
• Stood up an automated build pipeline: S3 for source, CodeBuild for builds, ECR for images — plus repeatable infra provisioning via AWS CloudFormation.
• Drove unit-test coverage from 0 to ~90%, improving system maintainability and integrity.
• Integrated core AWS data services: RDS (database), ElastiCache/Redis (caching), Amazon MQ (message broker).
• Optimized database queries through root-cause analysis; ran automated smoke and load testing with Grafana K6.

Web Developer (Intern) — Dashlabs.ai

Remote · Aug – Sept 2022

• Contributed to maintenance of the platform’s Patient Management Service.
• Handled customer queries across email and chat channels.

Selected Projects

Aqualytix — Water-Quality Monitoring Platform

• Built and deployed solo, end-to-end: Ruby on Rails + Hotwire, PostgreSQL, offline-first PWA, Prawn PDF reports, deployed via Kamal on AWS EC2 with CloudWatch monitoring.

Kuryente Watch — Real-Time Grid-Status App

• Built a Rails 8 + Hotwire crowdsourced PWA with a live Leaflet map and Web Push notifications; deployed via Kamal. Live at infanta.kuryentewatch.app.

Education

B.S. in Computer Science — Polytechnic University of the Philippines

2019 – 2023