Senior Frontend Engineer · Tech Lead

I build production-grade React apps for teams that ship fast.

Nine plus years turning complex product requirements into scalable web platforms. Now contributing to a micro-frontend platform and AI tooling at Nullplatform.

Open to senior, staff & lead frontend rolesSanta Fe, Argentina
Portrait of Walter Radduso

Trusted by teams at

  • Nullplatform logoNullplatform
  • Deel logoDeel
  • Mercado Libre logoMercado Libre
  • Mundi logoMundi
  • Endeev logoEndeev
About

Built for the boring parts that compound over time.

Bridging architecture, performance, and developer experience in modern React applications.

I help engineering teams ship reliable, accessible React applications without slowing down. My focus sits at the intersection of architecture, performance, and developer experience — the boring parts that determine whether a frontend stays maintainable past month six.

I have spent the last decade going from PHP and WordPress to leading frontend initiatives at MercadoLibre, building marketplace and fintech products at Mundi and Deel, and currently working on a micro-frontend platform and AI-powered developer tools at Nullplatform. I care about clean abstractions, honest code reviews, and shipping things that move metrics.

Experience9+ years
CurrentlyNullplatform
Based inSanta Fe, AR · GMT-3
StatusSenior · Staff · Lead
Spanish (Native)English (Upper Intermediate)
Experience

Where I've shipped production work.

Senior frontend roles across fintechs, marketplaces, and developer platforms — focused on shipping reliable React at scale.

  • Nullplatform logo
    Senior Frontend Engineer
    Jan 2025 — Present
    Nullplatform
    • Lead frontend architecture decisions across the internal developer platform, applying a micro-frontend approach to keep multiple product surfaces consistent and independently deployable.
    • Own a gateway service that bridges UI modules with backend APIs, reducing integration friction for every new frontend team that ships on the platform.
    • Integrate AI-powered features into the developer experience, building automation tools that shorten the path from idea to deployed feature.
  • Deel logo
    Senior Frontend Engineer
    Oct 2023 — Dec 2024
    Deel
    • Shipped frontend features for global hiring workflows used by thousands of customers, partnering closely with backend and product to maintain quality under high release velocity.
    • Drove code reviews and refactors that improved consistency across squads, reducing the cost of onboarding new engineers to the codebase.
  • Mundi logo
    Senior Frontend Software Engineer
    Nov 2022 — Oct 2023
    Mundi
    • Owned and evolved the cross-border financing dashboard used by SMB exporters in LATAM, focused on performance and conversion through reliable forms and async flows.
    • Established testing baselines and reusable form patterns that the rest of the frontend team adopted, lowering the bug surface in the most user-facing flows.
  • Mercado Libre logo
    Tech Lead Frontend
    Jan 2022 — Nov 2022
    Mercado Libre
    • Led frontend initiatives across multiple squads, defining technical direction in React and Node.js for high-traffic internal tools that supported marketplace operations.
    • Mentored mid-level engineers, ran technical interviews, and introduced lightweight RFCs to surface architecture decisions before they hit production.
  • Mercado Libre logo
    Senior Frontend Software Engineer
    Jan 2021 — Dec 2021
    Mercado Libre
    • Delivered frontend features across cross-functional squads, owning the React stack from component design to deployment and observability.
    • Drove code quality initiatives: introduced stricter review guidelines and refactored legacy modules into typed, tested components.
  • Mercado Libre logo
    Semi-Senior Frontend Software Engineer
    Oct 2019 — Dec 2020
    Mercado Libre
    • Built and maintained React and Node.js features across internal tools, adapting quickly to multiple product domains and stacks.
    • Contributed to migrations from legacy stacks to modern React, prioritizing incremental delivery and parity with existing flows.
  • Endeev logo
    Frontend Developer
    Jun 2016 — Oct 2019
    Endeev
    • Built React and React Native applications across multiple client projects, collaborating directly with product managers to shape requirements.
    • Contributed to RESTful APIs in Node.js to support the same products, gaining full-stack context and improving API/UI handoffs.
  • Freelancer · Tecnosan · 1st Outsourcing Choice logo
    Web Developer
    May 2011 — Jun 2016
    Freelancer · Tecnosan · 1st Outsourcing Choice
    • Built and maintained custom WordPress sites, RESTful APIs, and PHP-based user interfaces for local businesses and freelance clients.
    • Designed and shipped a regional e-commerce platform for Santa Fe, Argentina, enabling local merchants to publish and sell products online.
Selected Work

Things I've shipped lately.

A short list of recent work. Each one was a chance to ship something real to users, with measurable impact on the product or the team behind it.

Adopsys preview

Side project · Built end-to-end (frontend + backend)

Adopsys

Full-stack adoption platform that lets animal shelters move off spreadsheets — custom adoption forms, real-time chat between adopters and shelters, foster placements, post-adoption check-ins with scheduled crons, digital contracts, and verified shelter profiles.

Impact: Owned every layer in my own time: Next.js 16 frontend, Convex backend with real-time queries and cron-based follow-ups, OAuth + email auth, transactional emails via Resend, full ES/EN i18n, and a Playwright e2e suite. Live at adopsys.pet.

  • Next.js 16
  • React 19
  • Convex
  • TypeScript
  • shadcn/ui
  • next-intl
  • Resend
  • Playwright
Live
A new SaaS · In development preview

Side project · Building end-to-end (frontend + backend)

A new SaaS · In development

A new SaaS I'm building from scratch in my own time — designed, coded and shipped solo across the full stack.

Impact: Working on it with a modern stack: React frontend, serverless real-time backend, paid subscriptions, on-the-fly PDF generation, third-party data ingestion, multi-method auth, and PWA support.

  • Next.js 16
  • React 19
  • TypeScript
  • Serverless backend
  • Real-time queries
  • Subscriptions
  • PDF generation
  • shadcn/ui

Work in progress · MVP under construction

More on GitHub

Side projects and open-source experiments — pulled live from my GitHub.

More projects coming soon. In the meantime, check the featured work above.

Tech Stack

What I work with day to day.

From the core React stack to the AI tooling that's now part of how I ship. Opinionated about React and TypeScript, pragmatic about everything else.

Languages

  • TypeScript
  • JavaScript
  • HTML
  • CSS
  • GraphQL
  • SQL

Frameworks & Libraries

  • React
  • Next.js
  • Node.js
  • Express
  • React Native
  • Redux
  • Tailwind CSS
  • Sass

Tooling & DX

  • Git
  • GitHub
  • Vite
  • Webpack
  • Jest
  • Cypress
  • ESLint
  • Prettier
  • Storybook

Patterns & Practices

  • Micro-frontends
  • Design systems
  • Clean Architecture
  • Component-driven UI
  • REST APIs
  • GraphQL APIs
  • Performance optimization
  • Web accessibility (a11y)

AI & Workflow

  • Claude Code
  • Cursor
  • Windsurf
  • GitHub Copilot
  • Codex CLI
  • Antigravity
  • v0
  • n8n
  • Prompt engineering
  • Agentic workflows
Open to senior, staff & lead frontend roles

Looking for a frontend engineer who can lead?

I'm open to senior, staff and lead frontend roles, contract work, and consulting on React and Next.js architecture. Drop me a line and let's talk.

Email meConnect on LinkedIn
Or download my resume (PDF)

© 2026 Walter Radduso.