David Rodríguez Hidalgo

Career Profile

Senior Full Stack Engineer with 10+ years of experience, specializing in AI feature development, React, and Ruby on Rails. Built LLM-powered features at Factorial used by thousands. Proven track record of mentoring juniors, leading projects, and driving technical adoption (React, testing, GraphQL) from the ground up.

AI & Modern Development

AI Features
Built LLM-powered expense skill enabling natural language queries. Also developed bulk submission feature for file-to-expense automation at Factorial.
Testing & Quality
Established Jest + Cypress foundations at Nazaries; experienced with RSpec, Cucumber.
Frontend Evolution
Early adopter of React/Redux (2017), later GraphQL, TypeScript, Tailwind.

Experience

Senior Full Stack Engineer
Factorial Oct 2022 – Present
  • Led AI Initiative: Designed and built the Expenses AI Skill, enabling users to query expense data using natural language. Led development of bulk submission, allowing users to upload receipts/files and auto-generate expense reports – reducing manual entry time by an estimated 70%.
  • Domain Ownership: Owned full-stack development across Finance domain (Expenses, Software Subscription Management, Payment Policies), delivering Italy homologation (regulatory compliance) and budgeting tools.
  • Technical Stack: Ruby on Rails, React, TypeScript, GraphQL.

Technologies Used: Ruby on Rails, React, TypeScript, GraphQL, Resource Registry

Full Stack Developer
Camaloon Apr 2021 – Oct 2022
  • Architected and built a PrestaShop plugin and embroidery effect tool for the Atelier textile product line, enabling real-time product customization.
  • Led a full UX refactor of the Atelier section, increasing conversion by improving the customization flow.
  • Tech stack evolution: Adopted modern frontend standards (React, GraphQL, Tailwind) while maintaining Rails backend.

Technologies Used: Ruby on Rails, React, GraphQL, TypeScript, PHP

Ruby on Rails Developer → Consultant
Nazaries Jan 2014 – Mar 2021
  • Early React adopter: One of the first developers to introduce React (with Redux) to the company; also set up Jest and Cypress testing foundations that became team standards.
  • Led projects & mentored: Managed 3 junior developers while concurrently leading/contributing to up to 3 client projects (NGA, Amnistía Internacional).
  • Versatile delivery: Built and maintained full-stack applications using Rails (2, 3, 5), MySQL, Haml, Bootstrap, RSpec, and Cucumber.

Technologies Used: Ruby on Rails, React, Redux, MySQL, RSpec, Cucumber, Jest, Cypress

Projects

Northgate Arinso (NGA) - Web solution that reduces the complexity of global payroll by connecting cloud-based systems like Workday or SuccessFactors. Present in over 145 countries. Worked as an external contractor/consultant delivering UX improvements, new designs, and document management features.

Key Contribution: Led UX redesign and document management features as external consultant across multiple engagements.

Amnistía Internacional - Legacy platform to manage activists for the organization. Built with Ruby on Rails 3.

Key Contribution: Maintained and extended a large-scale activist management platform serving a major international NGO.

Aspro Parks - Ticketing platform for theme parks. Frontend developed with React and Ruby on Rails 4.

Key Contribution: First React + Rails integration at the company; set up frontend testing infrastructure.

Camaloon - E-commerce platform to design and sell custom products, with tools for product customization, storefronts, and integrations with Shopify, WooCommerce, and PrestaShop.

Key Contribution: Built the Print on Demand product line, PrestaShop plugin, and Atelier embroidery tool.

Other Notable Projects - Easystay (hotel customer experience platform – grew from solo project to team of 3, deployed in 12+ hotels), Fluetis (MVP marketplace platform with Rails API + React SPA), Ceres/Decidecrop (IoT greenhouse monitoring with weather stations and remote irrigation), Centre Pompidou (ticketing landing page integrated with Secutix API), Imperial Foundation (cancer research site – sole developer with direct client communication).