Joseph Karl Crisostomo

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

Summary

AWS-focused backend engineer who designs and operates relational databases on RDS — schema design, query optimization, automated S3 data ingestion, and CloudWatch monitoring — with Infrastructure as Code via CloudFormation.

Skills

• AWS: RDS, EC2, S3, CloudWatch, SNS, CloudFormation, ElastiCache (Redis), Amazon MQ, ECR, CodeBuild, EKS
• Databases: PostgreSQL, SQL views & indexes, query optimization, schema design
• Data / ETL: Python, automated CSV/data ingestion, S3-backed pipelines
• Backend: Ruby on Rails, Django, Node.js, REST integrations
• Tooling: Docker, Kamal, Grafana K6, Git, Claude Code

Experience

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

On-site · Feb 2024 – March 2026

• Integrated AWS data stores: RDS as the core database, ElastiCache (Redis) for caching, and Amazon MQ as a message broker.
• Conducted database query optimization through in-depth inspection and root cause analysis.
• Enabled fast, repeatable deployment by automating infrastructure provisioning with AWS CloudFormation.
• Built an automated build system using S3 for source storage, CodeBuild for builds, and ECR for container images.
• Managed containerized (Docker) services deployed on on-premise Ubuntu servers and on AWS.
• Initiated unit testing from 0 to ~90% coverage, improving system maintainability and integrity.
• Performed automated smoke and load testing with Grafana K6; implemented event-driven autoscaling with KEDA on Kubernetes.

Web Developer (Intern) — Dashlabs.ai

Remote · Aug – Sept 2022

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

Selected Project

Aqualytix — Water-Quality Monitoring Platform (PostgreSQL on AWS)

Solo, end-to-end · aqualytix.hackwithsef.xyz

• Built a production PostgreSQL platform with S3-backed file storage (Active Storage).
• Configured AWS CloudWatch monitoring — host metrics, log shipping, 5 alarms, and SNS email alerting.
• Deployed containerized to AWS EC2 with zero-downtime releases via Kamal.

Education

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

2019 – 2023