Available for Work

Federico Sapuppo

Ruby on Rails Developer

Mid-level Ruby on Rails Developer with hands-on experience building, testing, and maintaining production Rails applications. Strong background in backend development, APIs, databases, and cloud deployments. Experienced working remotely with international teams. Focused on Rails conventions, OOP principles, modern patterns, and delivering clean, maintainable, idiomatic, and beautiful Ruby code.

Ruby on Rails Contributor
Buenos Aires, Argentina (GMT-3)
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Federico Sapuppo
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Technical Skills

Backend

Ruby on Rails Ruby PostgreSQL REST APIs Trailblazer

Frontend

HTML5 CSS3 JavaScript React Tailwind Bootstrap

DevOps & Cloud

AWS (EC2, ECS, RDS) Firebase Git GitHub GitLab

Testing & Tools

RSpec Capybara Sentry Jira Asana Notion Claude Code Hermes

Open Source Contributions

Ruby on Rails Core
September 2024

Co-authored Rails Framework Enhancement

Co-authored a significant change to the Ruby on Rails framework that deprecated Sprockets as the default asset pipeline for new applications, establishing Propshaft as the new standard. This contribution involved updating test suites, removing legacy templates, and simplifying configuration files across the Rails codebase.

Commit: #52887 - No new apps should be started with sprockets
Impact: Affects all new Rails applications
Collaboration: Co-authored with 4 other contributors
View Contributor Profile View Commit on GitHub
Omarchy (Basecamp)
April 2026

T2 MacBook Support for DHH's Arch Linux Distribution

Contributed 5 merged PRs to Omarchy — DHH's opinionated Arch + Hyprland distribution — adding full T2 MacBook support. Fixes covered fan curves, keyboard backlight, battery indicator parsing, Bluetooth, and a migration script for existing installs. All shipped in Omarchy v3.5.0.

PRs Merged: #5132, #5135, #5137, #5145, #5176
Release: Shipped in Omarchy v3.5.0
Impact: Enables Omarchy on T2 MacBooks (2018–2020 models)
View Discussion T2 Customizations Repo
Linux Kernel (t2linux)
April 2026

Kernel Patch for Apple SMC Driver

Fixed a race condition in the applesmc kernel driver where 32-bit MMIO writes were clobbering adjacent single-byte registers, causing SMC command failures. Changed three iowrite32 calls to iowrite8, matching the ioread8 already used for the same registers.

PR: t2linux/linux-t2-patches#43
Impact: Fixes fan/thermal control on T2 MacBooks running Linux
Scope: 3-line kernel patch in applesmc driver
View PR on GitHub

Projects

Hermes

Marketing landing page for Hermes Agent — the self-improving AI agent by Nous Research. Built with modern web technologies.

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ARGPT

Argentine Portfolio Tracker — see your real USD return on assets bought with pesos, decomposed into stock vs. currency movement. Uses MEP/CCL rates.

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Contrarian Trifecta

Stock screening dashboard that surfaces contrarian DCA opportunities by combining fundamental quality, AI sentiment analysis, and technical floor detection.

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Work Experience

Ruby on Rails Developer with Accessibility Focus

U.S. Medical Application (Freelance)

Jan 2026 - Present
  • Accessibility: Implemented WCAG 2.1 AA accessibility improvements using semantic HTML, aria-label, and aria-describedby
  • Fixed screen reader issues caused by ambiguous links, unlabeled form fields, and non-semantic layouts
  • Improved color contrast and link visibility for users with low vision and color blindness
  • Validated accessibility compliance using WebAIM and industry guidelines (TPGi, Aditus)

Ruby on Rails Developer

Furbol (Part-time)

Jul 2024 - May 2025
  • Backend Development: Developed and maintained a Rails API supporting a Flutter mobile application following Trailblazer gem and design
  • Performance Optimization: Reduced AWS infrastructure costs by 60% through service reviews, query optimization, memoization, and API performance tuning
  • Reliability & Monitoring: Implemented Sentry for real-time error tracking and faster incident resolution
  • Notifications: Upgraded Firebase Cloud Messaging to HTTP v1, ensuring stable and reliable push notifications
  • Testing & Quality: Increased Rails API test coverage from 71% to 97% using RSpec
  • Feature Development: Implemented user blocking logic, booking system improvements, cron jobs, analytics integration, and rich snippets
  • Data & Localization: Optimized PostgreSQL queries, serializers, and implemented locale/translations improvements
  • Team Collaboration: Participated in sprint planning, backlog refinement, and collaborated with Flutter developers
  • Tooling: Adopted GitLab for version control and CI workflows

Ruby on Rails Developer on Testing & Automation

Medical American Company (Contract)

Feb 2024 - Jun 2024
  • Feature Cleanup: Removed legacy feature flags after the adoption of a new Rails engine
  • Testing: Wrote RSpec and Capybara unit and integration tests, ensuring full test coverage
  • Codebase Modernization: Improved maintainability and reduced technical debt
  • Open Source Contribution: Co-authored Rails framework enhancement that deprecated Sprockets as the default asset pipeline, affecting all new Rails applications

Ruby on Rails Developer

United Nations | UNFICYP (Volunteer)

Feb 2023 - Feb 2024
  • Full-Stack Development: Independently designed, developed, and deployed a Ruby on Rails application to streamline military operations
  • End-to-End Ownership: Managed requirements gathering, development, testing, and deployment
  • Deployment: Deployed and maintained the application on Render
  • Data Handling: Built structured data workflows to improve operational reporting and decision-making
  • Impact: Enhanced operational visibility for field teams

Ruby on Rails Developer

The Odin Project (Project-Based Training)

Dec 2021 - Oct 2024
  • Built a full-featured Rails application replicating core Facebook backend functionalities
  • Implemented authentication, associations, validations, and RESTful APIs
  • Applied MVC best practices, object-oriented design, and Git-based workflows

Education

Programming and Web Development

Self-taught & The Odin Project

2020 - 2026

Logic, Algorithms, Data Structures, Python, Ruby, Ruby on Rails, JavaScript, Object-Oriented Programming, SOLID design, REST, and modern web technologies

View Projects →

Logistics

Aeronautical University, Argentina

2019 - 2020

Pedagogy

Interamerican Open University, Argentina

2017 - 2018

Aircraft Systems

Aeronautical University, Argentina

2011 - 2014

The Blog

OffTheRails

Field notes from a Ruby on Rails developer who writes down every correction twice so he doesn't make it three times.

Rails Notifications AI Workflow

From 3 AM deploys to a notifications skill: shipping web push with Noticed and AI help

The last time I shipped push notifications, I did it from my bed at 3 AM. A few years later, on a different app, I had to do it again. This time, at scale: 25 legacy mailers, a feature flag, an AI workflow, and one nasty bug where push subscriptions leaked between users on the same laptop.

Federico Sapuppo · · ~8 min read
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Omarchy Arch Linux T2 Mac Kernel

If your MacBook falls off a desk, install Omarchy

My M3 Pro's screen cracked, my backup was a 2018 Intel MacBook Air that macOS had given up on, so I installed DHH's Arch distro on it. One discussion comment later, I was sending pull requests to basecamp/omarchy. Most merged within hours, and two days later they shipped inside Omarchy 3.5, plus a three-line kernel patch for the T2 SMC.

Federico Sapuppo · · ~7 min read
Read post

More stories coming soon

Bug autopsies, refactor diaries, and lessons from the Rails Way. New posts ship when they're worth your time.

Get in Touch

I'm currently available for freelance work and open to new opportunities. Fluent in English, native Spanish speaker, with knowledge of German.

fedesapuppo@hotmail.com
(+54) 9 3547468121
linkedin.com/in/federicosapuppo
github.com/fedesapuppo