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Senior Frontend / Fullstack engineer

Hello, I'm Jhonny

Fullstack engineer with 9+ years shipping production apps at scale. I build end-to-end systems and integrate AI into my workflow to move faster and deliver high quality software.

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Call me
Send an email
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Jhonny Menarim - Full Stack Developer
Frontend Engineer
Backend Developer
AI Orchestrator
Senior Full-Stack / Front-End Engineer with 9+ years of experience specializing in the React ecosystem (including Next.js and Remix), scalable Node.js/Javascript/TypeScript architectures, and high performance applications. Proven track record of architecting robust web platforms from scratch, modernizing complex codebases, and optimizing frontend performance to ensure seamless, low latency user experiences at scale. Adept at driving technical decisions, leveraging AI-assisted workflows, and delivering impact within distributed, international remote teams.

Frontend Skills

Core tools I use to build fast, accessible, and maintainable UIs.
  • JavaScript10yr
  • TypeScript10yr
  • React10yr
  • Next.js10yr
  • Tailwind CSS10yr
  • SASS10yr
  • Redux10yr
  • React Query10yr
  • tRPC10yr
  • Vite10yr
  • Webpack10yr
  • Zustand10yr
  • Vue10yr
  • Remix10yr
  • React Router 710yr
  • Styled Components10yr
  • CSS Modules10yr
  • React Testing Library10yr
  • Vitest10yr
  • Jest10yr
  • Cypress10yr
  • Service Workers10yr
  • Canvas API10yr
  • WCAG10yr
  • Gulp10yr

Backend Skills

Technologies I rely on to design scalable APIs and data pipelines.
  • Node.js10yr
  • GraphQL10yr
  • REST API10yr
  • MongoDB10yr
  • SQL10yr
  • Express10yr
  • Redis10yr
  • Elasticsearch10yr
  • Bull10yr
  • RabbitMQ10yr
  • Firebase10yr
  • PHP10yr
  • Laravel10yr
  • CodeIgniter10yr
  • Directus10yr
  • PostgreSQL10yr
  • NestJS10yr

Miscellaneous

Check the skills I have experience with, and for how long
  • Docker10yr
  • GitHub Actions10yr
  • CI/CD10yr
  • LLMs10yr
  • Cloudflare10yr
  • SEO10yr
  • E2E Testing10yr
  • WebOS10yr
  • Tizen10yr

Education

Bachelor degree

Computer Science2016 - 2022
UFPR - Universidade Federal do Paraná

Languages I speak

Portuguese - Native
English - Fluent/C1

Experience

Full-Stack engineer

Vizabli

Jan 2026 - Jun 2026

Upgraded legacy microservices, moving core dependencies from Node.js 12 to 24 and MongoDB from version 4 to 8

Refactored a 10-year-old codebase to run on modern Docker environments, fixing security flaws to bring open vulnerabilities from hundreds down to zero.

Optimized backend architecture and database index configurations, scaling application throughput from 10 to over 100+ requests per second (RPS).

Migrated version control and packages from AWS CodeArtifact to GitHub, setting up automated CI/CD pipelines with GitHub Actions

  • Stack:
  • JavaScript,
  • TypeScript,
  • Node.js,
  • React,
  • SASS,
  • Vite,
  • Styled Components,
  • CSS Modules,
  • AWS ECR,
  • AWS S3,
  • AWS EC2,
  • AWS CodeArtifact,
  • MongoDB,
  • Elasticsearch,
  • Redux,
  • Zustand,
  • Redis,
  • Bull,
  • RabbitMQ,
  • GitHub Actions,
  • CI/CD,
  • Docker,
  • LLMs,
  • Vitest,
  • Jest,
  • React Testing Library

Smart TV Front-End engineer

Fox Corporation

Jun 2025 - Dec 2025

Rebuilt the frontend application from scratch using Remix, React Router 7, and Tailwind CSS, shipping the entire production-ready platform within a tight 6-month timeline.

Optimized the UI to run smoothly on low-end hardware (2018 Tizen and WebOS models), cutting memory usage by 50% compared to the previous app version.

Wrote comprehensive unit and integration tests using Vitest and React Testing Library to ensure UI stability across different connected device manufacturers.

Delivered a unified codebase targeting four distinct Smart TV platforms (Tizen, WebOS, Comcast, Vizio), eliminating per-platform forks and reducing long-term maintenance overhead.

  • Stack:
  • JavaScript,
  • TypeScript,
  • Remix,
  • React Router 7,
  • Tailwind CSS,
  • SASS,
  • Firebase,
  • Tizen,
  • WebOS,
  • Comcast,
  • Vizio,
  • CI/CD,
  • LLMs,
  • Vitest,
  • Jest,
  • Cypress,
  • React Testing Library

Full-Stack engineer

World Pulse

Jan 2022 - Jun 2025

Built and architected the web platform from scratch using Next.js, Node.js, and GraphQL, handling the full infrastructure setup on AWS (EC2, RDS, S3).

Led technical decisions, sprint planning, task delegation, and code reviews within a distributed development team.

Managed the entire software development lifecycle, from scoping new features to deploying daily hotfixes and major releases.

Designed a type-safe API layer with GraphQL and tRPC, enabling the frontend to evolve independently from backend services without integration friction.

  • Stack:
  • JavaScript,
  • TypeScript,
  • Next.js,
  • Node.js,
  • GraphQL,
  • React Query,
  • tRPC,
  • Directus,
  • PostgreSQL,
  • NestJS,
  • AWS RDS,
  • AWS EC2,
  • AWS S3,
  • REST API,
  • Firebase,
  • CI/CD,
  • Vite,
  • Webpack,
  • Redux,
  • SASS,
  • CSS Modules,
  • Styled Components,
  • E2E Testing,
  • Jest

Smart TV Front-End engineer

Globo

Jan 2021 - Jan 2022

Developed user interfaces and core features for Globoplay, a high-traffic streaming application serving millions of active users.

Built reusable and performant React components utilizing Canvas Web APIs, ensuring compatibility across Samsung, LG, and Sony TV platforms.

Debugged and resolved complex performance bottlenecks and memory leaks inherent to high-scale data flows on hardware-constrained systems.

Enforced WCAG accessibility standards across all UI components, ensuring the platform met compliance requirements on Samsung, LG, and Sony TV devices.

  • Stack:
  • JavaScript,
  • TypeScript,
  • React,
  • Node.js,
  • GraphQL,
  • Canvas API,
  • WebOS,
  • Tizen,
  • WCAG,
  • Vitest,
  • Jest,
  • Cypress,
  • React Testing Library

Fullstack developer

Freelancer

Jan 2017 - Jan 2021

Developed a wide variety of web applications end-to-end, managing projects from initial UI layout to final cloud deployment and maintenance.

Built and integrated REST and GraphQL APIs using Node.js, Express, and PHP, connecting them with SQL and MongoDB databases.

Managed direct communication with clients to gather system requirements, balance technical debt, and provide long-term technical support.

Implemented PWA features including Service Workers and offline caching, alongside technical SEO optimizations that improved organic traffic and Lighthouse scores for client projects.

  • Stack:
  • JavaScript,
  • TypeScript,
  • Node.js,
  • Express,
  • PHP,
  • Laravel,
  • CodeIgniter,
  • React,
  • Vue,
  • Next.js,
  • GraphQL,
  • SQL,
  • MongoDB,
  • SASS,
  • Webpack,
  • Gulp,
  • Service Workers,
  • Cloudflare,
  • SEO

Achievements

Real results from real systems — two highlights that show what I focus on: throughput and efficiency.

At Vizabli, I scaled message processing from 10 to 200 items per second by combining queue concurrency tuning, parallelizing async operations, upgrading MongoDB, and eliminating database bottlenecks identified through profiling.

At Fox Corporation, the Smart TV app rewrite cut memory usage in half — from 240 MB down to 120 MB — by identifying and fixing memory leaks, eliminating render overhead, reducing unnecessary state, and optimizing component lifecycles for low-end hardware.

* Memory usage before vs after the full app rewrite

AI Integrated Workflow

I've been integrating AI into my workflow to boost efficiency — using it to speed up research, draft boilerplate, and catch edge cases early, while keeping full ownership of architecture and technical decisions.

Brainstorm and plan
AI pair programming
Code review
Write automated tests
Open pull request

Some projects I built

A selection of production apps I contributed to — spanning streaming platforms, Smart TV, social impact, and B2B SaaS.

Fox

Smart TV streaming app delivering 24/7 local news from FOX stations across major U.S. cities, built for Tizen, WebOS, Comcast, and Vizio platforms.

See moreVisit Fox Local website
Globoplay

Brazil's largest streaming platform by Globo, delivering live TV, on-demand series, films, and sports content to millions of subscribers nationwide.

See moreVisit Globoplay website
World Pulse

Global social impact network connecting women and allies across 233+ countries to share stories, build community, and collaborate on social change.

See moreVisit World Pulse website
Radar Gestão

Brazilian legal management platform providing consulting, recruitment, and professional development courses tailored for law firms and legal departments.

See moreVisit Radar Gestão website
7Place

Premium used vehicle dealership in Curitiba, Brazil, offering a curated selection of luxury and high-end cars with personalized service and financing.

See moreVisit 7Place website
Shift Car

Luxury and super sports car dealership in Curitiba, Brazil, featuring brands like Porsche, Lamborghini, and McLaren with nationwide delivery available.

See moreVisit Shift Car website

Open source projects

Tools and side projects I built and shared publicly.

jhonnyizidoro/strapi-generate-types

CLI tool for Strapi V5, published on npm, that auto-generates TypeScript interfaces from your schemas, covering components, collections, single types, and dynamic zones, eliminating manual type definitions across your project.

See moreView strapi-generate-types on GitHub
jhonnyizidoro/marriage

Personal wedding website featuring RSVP, song requests, and a gift registry integrated with Shopify, plus an admin panel for managing invitations and guests.

See moreView marriage project on GitHub