Joseph Karl Crisostomo

Full-Stack Engineer · Manila, PH (UTC+8) · joseph.dev.ph@gmail.com · +63 960 4431 908 Portfolio: https://kathulhur.github.io · GitHub: https://github.com/kathulhur

Summary

Full-stack engineer who builds internal tools and data-heavy web apps that operations teams actually use. I work across Python/Django and React/TypeScript, design and optimize databases, containerize services with Docker, and back my code with automated testing. I ship iteratively — requirements, prototype, deploy, feedback — and communicate clearly with both technical and non-technical stakeholders.

Skills

• Languages: Python, JavaScript, TypeScript, HTML, CSS, Ruby
• Backend / Web: Django, Node.js, Ruby on Rails, REST integrations, WebSocket/SSE
• Frontend: React, Next.js, HTMX, Turbo, Leaflet
• Databases: SQL, database design and query optimization, RDS, ElastiCache/Redis
• DevOps / Infrastructure: Docker, AWS (EKS, CloudFormation, S3, CodeBuild, ECR, RDS, Amazon MQ), on-premise Linux (Ubuntu), automated build pipelines
• Testing / Tooling: Unit testing, Playwright, Grafana K6, Git
• Strengths: Adaptive (picks up new tools fast), technology-agnostic, strong cross-functional communicator

Experience

Backend Developer — Department of Science and Technology, Advanced Science and Technology Institute (DOST-ASTI)

On-site · Feb 2024 – March 2026

• Built and maintained internal platform services in Python, deployed as containerized (Docker) applications on both an on-premise Linux server (Ubuntu) and on AWS.
• Initiated unit testing from 0 to ~90% code coverage, improving the maintainability and integrity of the system.
• Built and validated automated test workflows, including smoke and load testing with Grafana K6.
• Designed and tuned databases — performed query optimization through in-depth inspection and root-cause analysis; integrated RDS as the core database and ElastiCache (Redis) for caching.
• Built an automated build and deployment pipeline: source in S3, container builds in CodeBuild, images stored in ECR, infrastructure provisioned with AWS CloudFormation for fast, repeatable deployments.
• Orchestrated Docker containers with AWS Elastic Kubernetes Service (EKS) and integrated Amazon MQ as a message broker.
• Participated in code review and best-practice improvements across the team.

Web Developer (Intern) — Dashlabs.ai

Remote · Aug 2022 – Sept 2022

• Contributed to the maintenance of the platform's Patient Management Service.
• Handled customer queries across multiple channels (email, chat), supporting users directly.

Projects

AI-as-a-Service Platform (DOST-ASTI)

Internal platform standardizing how AI models are developed, deployed, and served across institutes — including a model/dataset repository and a feature to expose hosted models. Cut AI-model integration time from ~2–3 months to days. Technologies: Python, Docker, AWS.

Kuryente Watch

Community web app that crowdsources near-real-time electricity grid status so citizens can see outages and advisories at a glance. Built a map-based dashboard (React, Leaflet) and onboarded barangay "scouts" to report local outages. Link: https://infanta.kuryentewatch.app

Education

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

2019 – 2023