Looks like you have JavaScript disabled. For the full Twine experience, you will need to re-enable it.

I'm Eduardo Vargas Leffa, a Senior Software Engineer with over 10 years of experience building scalable, high-performance web applications. My primary focus is on React, Next.js, and TypeScript, with strong backend skills in Node.js, PHP, and SQL databases like MySQL and PostgreSQL. I design modular, clean codebases, integrate RESTful APIs, and deliver features from architecture to deployment. I thrive in fast-paced, collaborative environments and continuously apply SOLID principles, automated testing (Jest, Playwright, Cypress), and tooling like Docker, Git, and CI/CD. I work across frontend and backend layers to build end-to-end solutions, mentor teammates, and contribute to technical discussions that improve performance and reliability. I enjoy accelerating development with AI-assisted workflows (GitHub Copilot, ChatGPT), leading knowledge-sharing sessions, and delivering maintainable features with a focus on quality and scalability.…I'm Eduardo Vargas Leffa, a Senior Software Engineer with over 10 years of experience building scalable, high-performance web applications. My primary focus is on React, Next.js, and TypeScript, with strong backend skills in Node.js, PHP, and SQL databases like MySQL and PostgreSQL. I design modular, clean codebases, integrate RESTful APIs, and deliver features from architecture to deployment. I thrive in fast-paced, collaborative environments and continuously apply SOLID principles, automated testing (Jest, Playwright, Cypress), and tooling like Docker, Git, and CI/CD. I work across frontend and backend layers to build end-to-end solutions, mentor teammates, and contribute to technical discussions that improve performance and reliability. I enjoy accelerating development with AI-assisted workflows (GitHub Copilot, ChatGPT), leading knowledge-sharing sessions, and delivering maintainable features with a focus on quality and scalability.

Eduardo Vargas Leffa

Web Developer, Front-End Developer, Back-End Developer, +2





I'm Eduardo Vargas Leffa, a Senior Software Engineer with over 10 years of experience building scalable, high-performance web applications. My primary focus is on React, Next.js, and TypeScript, with strong backend skills in Node.js, PHP, and SQL databases like MySQL and PostgreSQL. I design modular, clean codebases, integrate RESTful APIs, and deliver features from architecture to deployment. I thrive in fast-paced, collaborative environments and continuously apply SOLID principles, automated testing (Jest, Playwright, Cypress), and tooling like Docker, Git, and CI/CD. I work across frontend and backend layers to build end-to-end solutions, mentor teammates, and contribute to technical discussions that improve performance and reliability. I enjoy accelerating development with AI-assisted workflows (GitHub Copilot, ChatGPT), leading knowledge-sharing sessions, and delivering maintainable features with a focus on quality and scalability.…I'm Eduardo Vargas Leffa, a Senior Software Engineer with over 10 years of experience building scalable, high-performance web applications. My primary focus is on React, Next.js, and TypeScript, with strong backend skills in Node.js, PHP, and SQL databases like MySQL and PostgreSQL. I design modular, clean codebases, integrate RESTful APIs, and deliver features from architecture to deployment. I thrive in fast-paced, collaborative environments and continuously apply SOLID principles, automated testing (Jest, Playwright, Cypress), and tooling like Docker, Git, and CI/CD. I work across frontend and backend layers to build end-to-end solutions, mentor teammates, and contribute to technical discussions that improve performance and reliability. I enjoy accelerating development with AI-assisted workflows (GitHub Copilot, ChatGPT), leading knowledge-sharing sessions, and delivering maintainable features with a focus on quality and scalability.

Available to hire

I’m Eduardo Vargas Leffa, a Senior Software Engineer with over 10 years of experience building scalable, high-performance web applications. My primary focus is on React, Next.js, and TypeScript, with strong backend skills in Node.js, PHP, and SQL databases like MySQL and PostgreSQL. I design modular, clean codebases, integrate RESTful APIs, and deliver features from architecture to deployment. I thrive in fast-paced, collaborative environments and continuously apply SOLID principles, automated testing (Jest, Playwright, Cypress), and tooling like Docker, Git, and CI/CD.

I work across frontend and backend layers to build end-to-end solutions, mentor teammates, and contribute to technical discussions that improve performance and reliability. I enjoy accelerating development with AI-assisted workflows (GitHub Copilot, ChatGPT), leading knowledge-sharing sessions, and delivering maintainable features with a focus on quality and scalability.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Intermediate

Language

English

Advanced

Portuguese

Fluent

Work Experience

Software Engineer at Visto Tecnologia

April 1, 2025 - Present

Developed and maintained internal systems using Vanilla PHP, Symfony, and Yii, improving system stability and enabling faster delivery of new features. Fixed frontend interfaces with JavaScript and React, enhancing usability, responsiveness, and user satisfaction. Resolved critical software bugs, managed support tickets, and contributed to technical discussions that improved overall system performance and reduced downtime. Integrated AI tools into daily workflows, leveraging GitHub Copilot and ChatGPT to accelerate development, refine ideas, and plan projects more efficiently. Initiated and led “Coffee with Learning,” a biweekly knowledge-sharing session that strengthened team integration and collaboration.

Senior Software Engineer Fullstack at Blue Technology

April 1, 2025 - September 21, 2025

Designed and implemented features using Node.js (backend) and Angular 16 (frontend), improving system scalability and maintainability. Optimized reporting by refining Sequelize ORM queries, significantly reducing response times and enhancing user experience. Refactored core modules with SOLID principles, MVC pattern, and database standardization, reducing technical debt and enabling future development. Standardized REST API and produced comprehensive endpoint documentation, improving integration speed and cross-team collaboration. Used Docker and GitLab CI/CD pipelines to automate deployments and ensure faster, more reliable releases.

Lead Software Engineer at Defensoria Pública do RS

October 1, 2024 - September 21, 2025

Migrated a large-scale system from AngularJS to React with Next.js, using feature flags for incremental rollout with zero downtime, improving performance and modernizing the tech stack without disrupting users. Implemented front-end architecture with React, Mantine UI library, Zod for validations, and Playbook as a design reference, increasing consistency and scalability. Led the end-to-end design, development, and delivery of scalable and reliable solutions, reducing technical debt and accelerating time-to-market for new features. Collaborated with cross-functional teams to define requirements and deliver high-impact, production-ready features. Mentored junior and mid-level developers through code reviews and knowledge-sharing sessions, improving team productivity and technical excellence.

Software Engineer at Turning

October 1, 2022 - September 21, 2025

Developed 50+ websites with React, Next.js, TypeScript, Tailwind CSS, TanStack Query, and PHP (Vanilla / CodeIgniter), delivering responsive, SEO-optimized solutions with improved performance and maintainability. Built e-commerce platforms using React, Next.js, and TypeScript, integrated with ERP/CRM systems, Ship, Shopify, Tray, Loja Integrada, and VTEX, optimizing checkout flows, reducing cart abandonment, and ensuring reliable email communication. Created dashboards with Vue.js, JavaScript, and REST APIs for a TV service sales system, implementing reusable components, dynamic filtering, and real-time updates. Migrated a j e w e l r y system from ASP to React/Next.js with TypeScript, PostgreSQL, Axios, TanStack Query, React Redux, and SendGrid, reducing technical debt and boosting performance. Led end-to-end development of responsive websites and cross-platform apps using React, Next.js, Tailwind CSS, and React Native.