React/Next.js Full-Stack Developer for AI-Powered SaaS Web Application

React/Next.js Full-Stack Developer for AI-Powered SaaS Web Application Job Description We are looking for an experienced React/Next.js developer to help build and improve an AI-powered SaaS web application. The project includes responsive frontend development, backend/API integration, authentication, database management, subscription payments, and AI features using OpenAI, Claude, Gemini, or similar APIs. The ideal developer should be comfortable taking ownership of complete features, from Figma designs and reusable UI components to backend logic, AI integrations, testing, and deployment. Key Responsibilities Build responsive interfaces using React, Next.js, and TypeScript Convert Figma designs into reusable components Develop dashboards, forms, tables, user profiles, and admin panels Implement authentication and role-based access Integrate REST APIs and third-party services Build backend functionality using Node.js or Next.js API routes Work with PostgreSQL, Supabase, or Firebase Integrate Stripe subscriptions and payments Build AI chat, content generation, summarization, and recommendation features Handle streaming responses, conversation history, and AI usage tracking Improve performance, fix bugs, test features, and support deployment Potential AI Features The application may include: AI chatbot or virtual assistant Content generation and rewriting Document summarization and data extraction Natural-language search AI-generated reports and recommendations Contextual responses based on stored user data Admin tracking for AI usage and costs Experience with embeddings, vector databases, RAG, or AI agents would be an advantage. Required Experience Strong experience with React.js, Next.js, and TypeScript Strong knowledge of JavaScript, HTML, and CSS Experience with Tailwind CSS or a similar framework Experience integrating REST APIs Experience with Node.js and backend development Experience with PostgreSQL, Supabase, or Firebase Knowledge of authentication and role-based access Experience with Redux, Zustand, React Context, or similar tools Strong Git and GitHub workflow Ability to work independently and communicate clearly AI Experience Experience integrating OpenAI, Claude, Gemini, or similar APIs Understanding of prompt engineering and structured responses Experience with streaming AI responses Ability to validate, store, and display AI-generated content Understanding of token usage, rate limits, API costs, and error handling Awareness of AI privacy and data security Nice to Have Experience with LangChain, LangGraph, or Vercel AI SDK Experience with embeddings and vector databases Experience with RAG or AI agents Experience with PDF or document processing Stripe subscription experience Testing experience with Jest, Playwright, or React Testing Library Deployment experience with Vercel, AWS, or Google Cloud Project Expectations We are looking for someone who can understand an existing codebase, recommend practical improvements, and deliver stable, production-ready features. The developer should be able to suggest suitable AI architecture without overengineering the solution or creating unnecessary API costs. This may become a long-term engagement based on performance. How to Apply Please include: A brief summary of your React and Next.js experience Two or three relevant project examples Details of an AI or chatbot feature you have implemented AI APIs, SDKs, or vector databases you have used Your weekly availability Your hourly rate or fixed-price estimate Please begin your proposal with “AI React SaaS.” Generic proposals without relevant project examples will not be considered. ## Recommended Upwork Skills * React.js * Next.js * TypeScript * JavaScript * Tailwind CSS * OpenAI API * Chatbot Development * RESTful API * Supabase * PostgreSQL * Firebase * Stripe * SaaS Development * API Integration * Responsive Web Design