Juan Lozano

I’m a Full Stack Engineer with over 6 years of experience independently building digital systems and products, specializing in scalable SaaS applications. I focus on designing clean architectures, making informed technical decisions, and building systems that are maintainable in the long term.

From scratch, I design and develop SaaS applications to solve real user problems, defining scalable architectures using NestJS and Next.js. I also build authentication and authorization systems (access control, user management), and develop bots and automations to improve user interaction and efficiency.

I’ve delivered real-world solutions like a personal financial management platform featuring a modular design for user clarity, full-stack development with Next.js, NestJS, and PostgreSQL, and secure authentication for sensitive data. In collaborative environments, I’ve contributed REST APIs with NestJS under authentication and separation of duties principles, built frontend interfaces with Next.js and React, and reinforced quality through practical unit and integration testing—always iterating based on real-world use, validation, and product improvement.