Gonzalo García Costoya
Frontend Developer
+54 9 223 668 6246 • gcostoya02@gmail.com • Mendoza, Argentina • linkedin.com/in/gonza-garcia • github.com/gonza-garcia
Professional Summary
Frontend Developer with more than 6 years building production React and TypeScript applications for US and Argentine companies, including more than three years on United Airlines' real-time flight-operations console: an event-driven app for flight operations that today replaces more than 30 legacy programs in production, with a WebSocket client layer, Redux Toolkit state management and AG Grid data views.
I build and maintain reusable UI components and shared libraries. One self-contained React library with its own store and API layer went through more than 50 published versions and is used in production by more than 3 teams. On the architecture side I led a cross-team React 16 to 19 migration across two teams and three shared libraries, moved the state layer from Redux and Redux Saga to Redux Toolkit and RTK Query, and cut the initial bundle by about 30 percent with code splitting and lazy loading.
I keep frontend applications testable, performant and observable: behavior and integration tests over complete user flows with Vitest and React Testing Library, V8 coverage thresholds above 70 percent with SonarQube reporting, and an end-to-end suite with Playwright. Advanced English with more than three years of daily communication with US-based clients. I have adopted AI agentic development as my main way of working day to day, using GitHub Copilot and OpenCode.
Open to Senior or Semi-Senior remote Frontend opportunities, and continuously learning across the React ecosystem and modern frontend tooling.
Skills
Work Experience
- Modernized and scaled United Airlines' FLIFO Flight Following console, an event-driven, real-time React app for flight operations that today replaces more than 30 legacy programs in production.
- Built a real-time WebSocket client layer with a Redux-slice connection state machine and auto-reconnect, consuming endpoints across 7 environments, from development to production.
- Designed a gradual migration plan: from Redux to Redux Toolkit as the state manager, and from Redux Saga to RTK Query for data fetching. It simplified and organized hundreds of generators and effect handlers, slowly saving thousands of lines of boilerplate code.
- Identified that one component could be encapsulated in its own library and created and published Flight Card: a reusable, self-contained React library with its own Redux store and API layer. Maintained it through more than 50 published versions, and today it is used in production by more than 3 teams within the company.
- Cut initial bundle size by about 30% with aggressive code splitting and lazy-loading dozens of modal chunks, through a custom wrapper over React.lazy, dynamic import and Suspense, used across multiple points in the app.
- Migrated the build toolchain from Create React App to Vite 6 and the test runner from Jest to Vitest 2, enforcing high V8 coverage thresholds of more than 70% in statements with SonarQube reporting. Kept the tests focused on app behavior and not on implementation details. Integration tests covered complete user flows.
- Led a cross-team migration from React 16 to React 19, coordinating synchronized upgrades across two teams and three shared internal libraries.
- Adopted AI agentic development (GitHub Copilot and OpenCode) as my main way of working, using skills and MCPs as quality gates to research, implement, review and test the output.
- Refactored large components into smaller modules and separated logic from presentation, improving maintainability and enabling smoother parallel team work.
- Created about 10 reusable React components with BBVA-branded variants, such as buttons, headers, menus, forms, dropdowns and sliders, implementing the official BBVA BentonSans type system and brand color palette.
- Built a standalone React and Redux insurance-quoting application from scratch, covering eight distinct insurance services, and defined the stack selection, library choices, and workflow design.
- Embedded custom React components as WordPress plugins within an Elementor-built marketing site, collaborating with two frontend developers on the integration layer between WordPress and React, including, among others, a carousel and a highly interactive header menu.
- Proposed and built a React app to generate Outlook HTML emails faster, cutting per-email time from about six hours to one hour. The team kept using it after my engagement without hiring a replacement.
- Hand-coded HTML emails for Outlook and restyled a ServiceNow internal web app with SCSS, collaborating directly with the client under Agile workflows.