Senior Full Stack MERN Developer

We are a U.S.-based SaaS startup looking for a Senior Full Stack MERN Developer to work directly with our hands-on CTO. This is a senior role for someone who can not only ship features but also improve architecture, enforce clean code practices, and scale an MVP into a production-grade SaaS platform.

We are prioritizing candidates based in Argentina or Brazil to align with U.S. West Coast (Los Angeles) working hours.

• Take ownership of an existing MERN MVP and evolve it into a scalable, production-ready product
• Refactor and improve messy or inefficient code for clarity, maintainability, and performance
• Debug and resolve complex cross-layer issues quickly (MongoDB, Node.js, React, CI/CD)
• Design and optimize MongoDB schemas, indexes, Atlas Search, and triggers
• Build event-driven workflows with MongoDB triggers
• Integrate AI/LLM services (OpenAI, AW...