Looking for Full-Stack Developer to Improve and Scale an AI Web Platform

We are looking for a skilled and reliable full-stack developer to help us improve and further develop our AI-based web platform. The project is already live, but we need a developer who can help us improve performance, fix bugs, polish the user experience, add new features, and make the platform more stable and scalable. We are looking for one serious individual developer, not an agency. What we need help with: Improving the current web application Fixing bugs and technical issues Improving frontend design, responsiveness, and user experience Working with API integrations Improving backend logic and performance Helping with payments, subscriptions, credits, and user accounts Making the platform more stable and production-ready Suggesting better technical solutions when needed Ideal candidate: Strong experience with modern web development Good knowledge of frontend and backend development Experience with AI APIs or SaaS platforms is a big advantage Experience with payment systems such as Stripe is a plus Can work independently and communicate clearly Can understand an existing codebase quickly Honest, reliable, and detail-oriented Tech stack: Our platform is built as a modern web application. Experience with technologies like Next.js, React, Node.js, TypeScript, APIs, databases, authentication, and Stripe would be very useful. Important: We are not looking for someone who only writes code blindly. We need a developer who can understand the product, find problems, suggest improvements, and help us build something better. This can become a long-term cooperation if the first tasks go well. Please include in your application: Your experience with SaaS or AI-related platforms Examples of web applications you worked on Your experience with APIs, payments, and user account systems Whether you work alone or as part of an agency Your hourly rate or fixed-price preference When you can start Thank you.