Senior Frontend Engineer | React, TypeScript, Microfrontends & Design Systems
Hi! I'm Lucas Guinalia Ruy, a Senior Frontend Engineer with 9+ years of experience building scalable, high-performance applications with React + TypeScript.
I specialize in microfrontend architectures, design systems, and monorepos — and I thrive in complex, large-scale environments. Currently acting as a technical reference for 15+ teams simultaneously, leading frontend architecture decisions through ADRs and RFCs, and maintaining systems with 40+ remote microfrontends in production.
My work spans critical products — from a payment checkout processing ~R$ 390M/month at PagSeguro PagBank, to strategic banking portals at GFT Technologies.
I'm passionate about turning architectural complexity into scalable, maintainable solutions — and about enabling teams to ship faster and with higher quality.
Frontend: React, Next.js (SSR, SSG, ISR), TypeScript, JavaScript (ES6+), Redux, Zustand, React Query, React Hook Form, Zod, Astro.js
Architecture & Tooling: Module Federation, Microfrontends, Design Systems, Storybook, Webpack, Vite, RSPack, Rollup, TurboRepo, Monorepos, Feature-Sliced Design (FSD)
Testing & Quality: Jest, React Testing Library (RTL), Cypress, ESLint, Prettier, SonarCloud, DangerJS, Testing Pyramid, Triple A pattern
DevOps & Infra: CI/CD (GitHub Actions, Azure DevOps, GitLab CI), npm packages, Docker, New Relic, Splunk, Sentry
Backend (support): Node.js, NestJS, Express, BFFs, REST APIs
Also: ADRs, RFCs, Technical Documentation, Agile/Scrum, Mentoring
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GFT Technologies (2025–now): Technical reference for 15+ teams in a large-scale bank. Responsible for a backoffice host app with 40+ remote MFEs and a merchant/partner portal with 10+ remote MFEs — both using Module Federation + Vite. Leading ADRs, RFCs, private npm packages and boilerplates to eliminate code duplication across the organization. Also driving AI-powered Developer Experience initiatives: built custom GitHub Copilot agents with skills, templates and scripts to standardize access to frontend patterns and reduce recurring questions about MFE integrations — and developed an MCP Server that queries the Design System's Storybook via Playwright, enabling developers to get component guidance directly from the AI assistant.
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Arcotech (2021–2025): Defined the monorepo strategy with Turborepo, built the internal MFE communication library adopted by 6 teams (12+ frontend devs), created New Relic integration standards and synthetic monitors with real-time Slack alerts, and mentored engineers across all levels.
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PagSeguro PagBank (2020–2021): Developed the SSR-based payment checkout (Next.js) responsible for processing ~R$ 390M/month, with PIX support and multiple card brands. Built BFF endpoints and implemented observability with New Relic and Splunk.
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Leroy Merlin (2019–2020): Revamped the homepage and implemented the loyalty program, increasing conversion and customer engagement across mobile and desktop.
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Enext / NewBlue / Freelance (2015–2018): Grew from junior to mid-level in under a year. Built e-commerces, animation-heavy landing pages, and VTEX/Oracle Commerce Cloud solutions.
- English proficiency (intermediate, actively improving)
- Advanced observability and monitoring in large-scale frontend systems
- Frontend architecture patterns, performance optimization and platform thinking
Always seeking clarity, performance, and sustainable solutions.
Let's build something amazing!