// senior ruby on rails engineer · manila, philippines · remote
marc@portfolio: ~/whoami
$ whoami

Marc Jesus
Caabay

$ cat role.txt

Senior Ruby on Rails engineer · scalable SaaS & enterprise systems · AI-assisted delivery with Claude Code

10+ years shipping production Rails at scale. I design SaaS platforms, modernize legacy monoliths, and run an AI-assisted pipeline that turns tickets into reviewed, deployed pull requests — without lowering the quality bar.

$ ./status --live

▸

10+ years Rails Enterprise SaaS AI-assisted engineering International remote teams Available for new work
01

what i help companies build

// eight things founders and engineering leaders bring me in for
SaaS platforms

Multi-tenant Rails apps with subdomain routing, roles, billing, and background jobs — designed to scale from launch to enterprise.

Enterprise applications

Internal systems that hold up under real workloads — reporting, workflows, integrations, and audit trails.

APIs & GraphQL

REST and GraphQL surfaces designed for versioning, pagination, auth, and typed clients from day one.

Legacy Rails modernization

Upgrade Rails, split fat models, extract services, add tests, and unstick teams stuck on old versions.

Performance optimization

Profile slow queries, kill N+1s, add the right indexes and caches, and shave real seconds off request times.

AI integrations

Ship LLM features that actually work in production: OpenAI & Claude APIs, prompt engineering, evals, MCP.

Internal business systems

Ops tools, admin dashboards, and internal workflows that replace spreadsheets and unblock revenue teams.

Technical architecture

Design the boundaries, data model, and deploy story so features stay easy to ship a year from now.

02

featured case study

🔒 rsvp.marcjesuscaabay.dev
RSVP dashboard

RSVP

LIVE
// role: solo engineer · design, architecture, build, ship

Multi-tenant event platform. Hosts spin up a branded subdomain (yourwedding.rsvp.app) to run the whole event — RSVPs, meal preferences, dietary notes, waitlists, themeable public pages, co-admin invites, and a shared "disposable camera" gallery. Timezone-aware dashboard with exports.

// stack
Rails 7.2 PostgreSQL Next.js 15 TypeScript Tailwind Sidekiq Cloudinary
Problem

Event hosts were juggling Google Forms, spreadsheets, and group chats for RSVPs, meals, and guest photos — losing information at every hop.

Solution

One branded subdomain per event with RSVP flow, meal/dietary capture, waitlisting, themeable public pages, and a shared gallery.

Architecture

Rails 7.2 API + Next.js 15 front-end, subdomain-scoped tenants, Sidekiq for email & image jobs, Cloudinary for uploads, timezone-aware scheduling.

Outcome

Hosts run an entire event from one dashboard. New event = new subdomain in seconds. Live product, real guests, exportable data.

03

ai engineering workflow

Daily practitioner of AI-native engineering. Claude Code is not autocomplete here — it's an orchestrated part of the delivery pipeline, with humans on the critical path.

"AI compresses time. It does not replace judgment."

01
Ticket → spec
Turn a Jira ticket into a clear spec: intent, constraints, acceptance criteria, out-of-scope.
02
Plan & test cases
Write the implementation plan and the tests it needs to pass — before a single line of code.
03
Architecture check
Decide boundaries, data changes, migration story, and rollout — this is where a senior engineer earns their keep.
04
Implementation
Claude Code executes the plan against a real repo, with human review at each meaningful edit.
05
Tests
Unit + integration + regression, run locally and in CI. Green build is table stakes, not the goal.
06
Self review
Adversarial pass on the diff: security, edge cases, backwards compatibility, hidden coupling.
07
Pull request
Clean commit history, PR description that explains the why, screenshots when it matters.
08
Deploy & observe
Ship behind a flag when it warrants one. Watch metrics and logs after. Fix forward.
$ claude --agent ship-feature --from jira --to pull-request
04

stack

// backend
Ruby on Rails
Ruby
Python
FastAPI
GraphQL
// frontend
Next.js
React
TypeScript
Tailwind CSS
// data
PostgreSQL
MySQL
Redis
Sidekiq
// cloud & devops
AWSAWS
Docker
GitHub Actions
Buildkite
Vercel
Railway
// ai & agents
Claude Code
Anthropic API
OpenAI API
◇Prompt Engineering
⣿MCP & Agents
// practices
TDD Agile Code Reviews REST & GraphQL APIs CI/CD System Design
05

recommendations

// received via linkedin
“
Marc is highly knowledgeable in web development and consistently delivers quality work, but what I appreciate most is that he never stops learning. Despite his experience as a Senior Web Developer, he's always open to new ideas, technologies, and better ways of doing things. He's also a trusted teammate who is dependable, easy to work with, and always willing to help others when needed.
JB Jeoff Balaga Full-Stack Digital Marketer Managed Marc directly · May 2026
“
I had the opportunity to work with Marc during the early days of Speed.ai where I got to appreciate not only his talent and familiarity with the Ruby on Rails framework, with which he has worked for many years, but also his attention to detail and work-ethic. I am happy to give him my recommendation as a solid Ruby on Rails engineer and, in general, developer.
ID Innocent Díaz Rails Engineer · Product at SpeedAI Managed Marc directly · March 2026
$ ./contact.sh

Looking for a senior Rails engineer?

Open to senior full-time, contract, and consulting work with international SaaS teams. Fastest response: email.

Full-time Contract Consulting Technical architecture
✉ caabaymarcjesus@gmail.com
in LinkedIn GitHub