I build apps used by millions.
I'm Oscar Martínez, a senior software engineer with 8+ years building web and mobile apps used by millions — Spin by OXXO, Aeroméxico. Specialized in React Native, React, Node.js, .NET, AWS and AI-augmented workflows, I help businesses take their product from idea to production.
Products I've helped build.
Aeroméxico's new mobile app is how millions of passengers across Mexico and LATAM book, check in and travel. I build the screens and reusable components that keep that experience fast and reliable at enterprise scale.
React Native with TypeScript, integrating microservices and backend APIs across a distributed architecture. Strict code standards, performance optimization and clean architecture required for enterprise-level reliability.
A contracting company was running its whole operation on spreadsheets — cities, materials and meter data, scattered and manual. I built them a custom ERP from scratch that centralizes it into one place, so their team stops losing hours to manual tracking and works from a single source of truth.
.NET 7 backend with SQL Server and a mobile-first React PWA (Tailwind). JWT authentication, AWS S3 storage, and admin modules for cities, materials and meters. Deployed to QA and production on Ubuntu with Nginx, HTTPS (Let's Encrypt) and CI/CD pipelines.
Spin Premia and Spin by OXXO are fintech apps used by millions across Mexico — loyalty, payments and rewards. I helped build and maintain the features that keep those apps dependable for a massive daily user base.
React Native, Redux and TypeScript, with TDD in Jest at 85%+ coverage per pull request. QA and production releases managed through Firebase, following SCRUM.
For Sumitomo Corporation, a global enterprise, I helped deliver internal web applications that streamline how their teams work — built fully remotely alongside US stakeholders.
React, Redux, TypeScript and DevExpress on the front, SQL Server services on the back, with TDD in Jest. Deployed to Microsoft Azure, collaborating in Agile teams across time zones.
Terminal Logistics moves high volumes of freight, and their operation runs on custom software. I led development of the logistics tools that keep that throughput flowing, day in and day out.
React, React Native, Redux, Node.js and C#/.NET, managing SQL Server and MongoDB databases built for high-throughput logistics operations.
From the problem to a product that survives production.
Mobile apps
iOS and Android apps your customers actually want to use — from prototype to the App Store, built on the same foundation behind products used by millions.
Web platforms & apps
The web platform your business needs, built to last and grow with you — end to end with React/Next.js and Node.js or .NET, with tested code, not fragile prototypes.
Custom systems & ERPs
Systems, ERPs and dashboards that automate the manual work slowing your team down — like the ERP I built from scratch, end to end, for a client.
Integrations & automation
Connect your software to payments, third-party services and the cloud — REST APIs and integrations deployed on AWS or Azure, ready for production from day one.
Product rescue & improvement
Already have something that stalled, broke or grew hard to maintain? I step in to stabilize, optimize and move your existing product forward — without rewriting what already works.
I don't just write code. I ship products that work.
I'm a senior software engineer with 8+ years building high-traffic mobile and web applications for companies of every size. I've shipped products used by millions —Spin by OXXO, Aeroméxico— and delivered custom systems end to end as a freelancer.
I work with clean architecture, tested code and clear communication — so what I build keeps working, and you always know where your project stands. For 2+ years I've collaborated daily with US teams, fully remote and in English.
Whether you need a new app, a custom system or to rescue a product that stalled, I can take it from idea to production.
Let's build something?
Tell me what you have in mind — an idea, a half-finished project or something you want to build from scratch. I reply to every message and, if I'm not the right person for it, I'll tell you honestly.
oscar.170993@gmail.com →