Gelson Mariano Rodrigues

Senior Frontend Engineer · React · TypeScript · Next.js · React Native

Remote from Brazil (UTC-3). Available for remote roles with US-hours overlap.

About

I'm a Senior Frontend Engineer with 13+ years of experience building high-performance web and mobile applications across fintech, healthcare and enterprise retail. I specialize in React, TypeScript, Next.js and React Native, with a deep focus on design systems, micro-frontends and AI-assisted development workflows.

I care about interfaces that feel fast and clear, and I measure the impact: conversion lifts, faster releases, accessible products shipped end-to-end on the frontend.

Highlights

Experience

Senior Frontend Engineer · Gen Digital

New York, US (remote) · –

  • Optimized the main "instant-access loan" conversion funnel by building and testing UI variants: +105% widget engagement, +32% lead generation, +$54k weekly revenue.
  • Built cross-platform React Native features for personal finance management, covering navigation, state handling and REST API integrations.
  • Moved the core blog from WordPress to Next.js with the Consumer Marketing team, improving Core Web Vitals and load times.
  • Built high-traffic pages for global marketing campaigns, including one with creator MrBeast.

Senior Frontend Engineer · Afya

Rio de Janeiro, Brazil (remote) · –

  • Architected and launched WB Expert, a Next.js + TypeScript Progressive Web App that distributes clinical guidelines to doctors.
  • Implemented end-to-end telemetry with Snowplow and Braze to guide medical content and course decisions.
  • Built a content delivery architecture serving 5,000+ articles with low latency and zero layout shift.

Senior Frontend Engineer · Lend

São Paulo, Brazil (remote) · –

  • Built the frontend of an automated loan approval web app with Next.js and TypeScript.
  • Refactored the core codebase for type safety and standardized data fetching with React Query.
  • Launched the company's marketing website from scratch in 48 hours with Next.js and TailwindCSS.

Senior Frontend Engineer · MZ Group

São Paulo, Brazil (remote) · –

  • Led the migration from a monolith to micro-frontends with Webpack Module Federation and decoupled CI/CD, taking release approvals from 7+ days to zero.
  • Built an investor relations dashboard with React and visx, unifying financial metrics and stock market data in real time.

Frontend Engineer · Luizalabs (Magalu)

Franca, Brazil (on-site) · –

  • Built 5+ React Native store logistics apps, deployed via MDM across 1,000+ stores with offline-first sync.
  • Developed mobile inspection tools for reverse logistics, used to grade product damage and speed up inventory intake.
  • Wrote Python data extraction scripts with data engineering to move store metrics into the data warehouse.

Frontend Engineer · SMN TI

Franca, Brazil (on-site) · –

  • Founding frontend engineer: built the original AngularJS component library for the flagship real estate ERP, later ported to Angular 2+ and open-sourced.
  • Built a supply billing tracking app for retail client Magalu and an internal workforce management app, leading a squad of 6.
  • Set frontend standards and build tooling, and mentored 5 junior developers and interns.

Skills

Languages and core
TypeScript, JavaScript, HTML5, CSS3/SASS, Python (scripting)
Frontend and state
React, Next.js, React Native, React Query, Redux (Saga/Thunk), Valtio, Recoil
UI, styling and design systems
TailwindCSS, Styled Components, Storybook, Reshaped, Material UI, visx
Testing, tooling and AI
Jest, React Testing Library, Cypress, Webpack (Module Federation), Chromatic, Cursor, Claude Code
Cloud, DevOps and observability
AWS, Google Cloud, Vercel, Cloudflare, Datadog, Sentry, Snowplow, Growthbook, Harness

Education and certifications

Languages: English (advanced, full professional proficiency), Portuguese (native).