I build apps used by millions.
I'm Oscar Martínez, a senior software engineer with 8+ years building high-traffic mobile and web applications — from Spin by OXXO to Aeroméxico. Specialized in React Native, React, Node.js and .NET.
Eight years shipping products used by millions.
Building screens and reusable components for Aeroméxico's new mobile app, serving millions of passengers across Mexico and LATAM. Microservice integration and enterprise-grade clean architecture.
Designed and built a custom ERP for electrical contractors end-to-end: .NET 7 backend with SQL Server and a React frontend (mobile-first PWA). JWT auth, AWS S3 storage and CI/CD deployment on Ubuntu/Nginx.
Built and maintained the B2C apps Spin Premia and Spin by OXXO, used by millions across Mexico and LATAM. TDD with Jest (85%+ coverage per pull request) and Firebase deployments under SCRUM.
Enterprise web apps for Sumitomo Corporation in fully remote, English-speaking teams. React, Redux and TypeScript, SQL Server services, TDD with Jest and deployment to Microsoft Azure.
High-volume logistics solutions with React, React Native, Node.js and C#/.NET. Managed SQL Server and MongoDB databases for high-throughput operations.
From the problem to a product that survives production.
Mobile apps
iOS and Android apps with React Native, from prototype to store. The same foundation I used to build products used by millions.
Full-stack web apps
Custom front and back with React/Next.js and Node.js or .NET. Clean architecture and tested code, not fragile prototypes.
Custom systems & ERPs
Internal systems, ERPs and dashboards that automate your operation — like the ERP I built from scratch, end-to-end, for a client.
APIs, integrations & cloud
REST APIs, third-party integrations and deployment on AWS or Azure with CI/CD. Everything delivered production-ready.
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. I've shipped products used by millions —Spin by OXXO, Aeroméxico— and delivered custom systems end-to-end as a freelancer.
I work with TDD (85%+ coverage), clean architecture and AI-augmented development workflows. For 2+ years I've collaborated daily with US teams in fully remote, English-speaking environments.
If you need an app, a custom system or to improve an existing product, I can help you end to end.
Let's build something?
Tell me what you have in mind. I reply to every message and, if I'm not the right person for your project, I'll tell you honestly.
oscar.170993@gmail.com →