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

Hi, I'm Sergio – a Full-Stack Software Engineer focused on the modern web stack (Next.js, TypeScript, and Node.js). I enjoy turning complex business requirements into scalable, reliable web products with a mobile-first mindset and a strong emphasis on end-to-end automated testing. I'm actively looking for remote opportunities where I can contribute to high-performance web products and collaborate with product teams to ship value quickly.…Hi, I'm Sergio – a Full-Stack Software Engineer focused on the modern web stack (Next.js, TypeScript, and Node.js). I enjoy turning complex business requirements into scalable, reliable web products with a mobile-first mindset and a strong emphasis on end-to-end automated testing. I'm actively looking for remote opportunities where I can contribute to high-performance web products and collaborate with product teams to ship value quickly.

Sergio Fabian Acuña Madrid

Full Stack Developer, Web Developer, Front-End Developer, +3





Hi, I'm Sergio – a Full-Stack Software Engineer focused on the modern web stack (Next.js, TypeScript, and Node.js). I enjoy turning complex business requirements into scalable, reliable web products with a mobile-first mindset and a strong emphasis on end-to-end automated testing. I'm actively looking for remote opportunities where I can contribute to high-performance web products and collaborate with product teams to ship value quickly.…Hi, I'm Sergio – a Full-Stack Software Engineer focused on the modern web stack (Next.js, TypeScript, and Node.js). I enjoy turning complex business requirements into scalable, reliable web products with a mobile-first mindset and a strong emphasis on end-to-end automated testing. I'm actively looking for remote opportunities where I can contribute to high-performance web products and collaborate with product teams to ship value quickly.

Available to hire

Hi, I’m Sergio – a Full-Stack Software Engineer focused on the modern web stack (Next.js, TypeScript, and Node.js). I enjoy turning complex business requirements into scalable, reliable web products with a mobile-first mindset and a strong emphasis on end-to-end automated testing.

I’m actively looking for remote opportunities where I can contribute to high-performance web products and collaborate with product teams to ship value quickly.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Language

Spanish; Castilian

Fluent

English

Advanced

Work Experience

AI Legislative Assistant (Freelance Developer) at Self-Employed / Freelance

November 1, 2025 - Present

Engineered a production-ready AI conversational agent specialized in a legislative representative's public profile. Architected a type-safe frontend using React and TypeScript, ensuring a robust and maintainable codebase. Integrated the Google Gemini API within a Node.js/Express backend to process natural language queries in real-time. Implemented advanced prompt engineering techniques to strictly control the AI's persona, ensuring accurate, institutional responses and mitigating hallucinations regarding legislative data.

QA Engineer & Full-stack Intern at Bitam de México

January 1, 2026 - May 1, 2026

Engineered automated scripts using Playwright and TypeScript to streamline repetitive data-entry workflows within the core SaaS, eliminating manual operational tasks and improving execution speed. Architected a full-stack Bug Tracker MVP (Next.js, TypeScript, Prisma, PostgreSQL) to evaluate high-performance issue-reporting workflows, integrating strict Zod validation pipelines to ensure data integrity.

Freelance Developer at AI Legislative Assistant

November 1, 2025 - Present

Architected a full-stack AI conversational agent using React.js, TypeScript, and Node.js, integrating the Google Gemini API to process natural language queries in real-time. Implemented advanced prompt engineering to strictly control the AI's persona, ensuring accurate institutional responses and mitigating hallucinations regarding legislative data.

Frontend Engineer / Mobile-First MVP Architect at Yama Japanese Food

January 1, 2026 - February 1, 2026

Architected a Mobile-First digital menu using Next.js and Tailwind CSS, optimizing the UI/UX around QR code scanning to modernize the traditional dining experience. Optimized rendering performance to ensure immediate load times on mobile networks, significantly reducing bounce rates.

Full-Stack Web Developer at Family Cookbook

September 1, 2015 - December 1, 2015

Developed a full-stack application to digitize family recipes, architecting a robust data flow between a React frontend, a Node.js API, and a PostgreSQL database. Engineered a scalable media management system integrating the Cloudinary API for secure image storage and optimized content delivery (CDN).

Frontend Engineer / Progressive Web App at Silent Beauty

December 1, 2025 - March 1, 2026

Engineered a pixel-perfect, progressive web app designed for photography. Achieved a perfect 100/100 Google Lighthouse score across Performance, SEO, and Accessibility. Solved complex cross-browser compatibility issues (iOS/In-App Browsers) using modern CSS viewports and adaptive Flexbox layouts.