We are looking for an experienced developer to work on the evolution of a modern SaaS platform that integrates artificial intelligence, automation, and recurring payments. The project already has a functional base and aims to reach a commercial level with refined design and high performance. The system uses modern technologies such as Next.js (React), Node.js (NestJS), Prisma (PostgreSQL), and integrations with Stripe and Mercado Pago, in addition to Python (FastAPI) modules for AI features. We are seeking professionals with proven experience in SaaS development, scalable architecture, and payment or AI integrations. The work involves improving, optimizing, and integrating existing modules, not rebuilding the system. Requirements: Strong experience with Next.js, Node.js, Prisma, Stripe, Mercado Pago Clean, modular code and proper GitHub versioning Organized, demonstrable deliveries (videos or staging environment) Clear communication and commitment to deadlines Important: When applying, please share links to SaaS, marketplace, or AI-integrated platforms that you personally developed. Avoid generic links. If possible, include short videos showing the source code running to confirm authorship and technical ownership. Industry: Technology and intelligent automation applied to digital services and certification systems. Technical Level: Advanced — preferably with a background in developing complete products (frontend, backend, and integrations).