Joseph Karl Crisostomo

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

June 25, 2026

Dear Hiring Team,

I’m writing to apply for the Back-End Developer (Rails/PostgreSQL) role supporting your managed services on the Neyo platform. The way you framed this seat — back-end work where how you think about systems matters most, built with Claude Code in a spec-driven workflow — describes exactly how I already work.

I build production Rails and PostgreSQL systems and own the decisions that determine whether they scale. For Aqualytix, a monitoring platform I built and deployed solo, I designed the full domain model, added background alerting and email notifications, and deployed it zero-downtime with Kamal to AWS EC2 under CloudWatch monitoring. For Kuryente Watch, a Rails 8 application, I modeled an append-only event log over PostgreSQL with JSONB boundary data and fanned out notifications through background jobs and Action Cable — the kind of event-driven design that has to behave well as volume grows.

That instinct for scale comes from production experience. At the Advanced Science and Technology Institute I optimized database queries through root-cause analysis, ran Redis caching and a message broker, and load-tested with k6. I care about clean data models and proper indexing because I have seen what shortcuts cost later.

On AI tooling: I write the spec and own the architecture, then pilot Claude Code against it. My raw-coding background lets me catch when the work drifts before it ships — so AI is a force-multiplier, not a substitute for judgment. I am coachable, communicate clearly in writing, and want to grow into harder architecture problems with a team that invests in its people.

I would welcome the chance to walk you through either system’s data model. Thank you for your consideration.

Sincerely,

Joseph Karl Crisostomo