Freelance Full-Stack Developer (Interactive Web Products)

This is a freelance role for a Tendem project. As a Full-Stack Web App Developer, you'll design, build, and refine browser-based applications with real logic, state, persistence, and user input - from habit trackers and budgeting tools to internal dashboards, mini-SaaS tools, and AI-powered apps. You may also work on standalone Python applications and data-processing scripts that sit alongside or behind these products.

- Build interactive web applications with frontend (React, Next.js, Vue, or similar) and a backend API (Python/FastAPI/Flask or Node/Express). - Design and implement data models, schemas, and persistence layers using SQL (PostgreSQL, SQLite) or NoSQL stores. - Implement authentication, sessions, and basic role-based access where needed. - Integrate third-party APIs and AI/LLM services (OpenAI, Anthropic, or similar) into product features. - Handle state management, user input validation, error states, and loading states cleanly. - Build standalone Python tools and scripts where required by the task (data processing, API clients, lightweight backend utilities). - Evaluate AI-generated full-stack code and refactor it for correctness, security, performance, and maintainability. - Write clear, testable code and debug end-to-end issues across frontend, backend, and database.

- At least 3 years of relevant experience in full-stack web development or shipping interactive web applications (required) - Bachelor's or Master's Degree in Computer Science, Engineering, Information Technology, or related technical fields is a plus - Candidates should have a strong foundation in full-stack web development, modern frontend frameworks, backend architecture, and building interactive browser-based applications end-to-end.

We are looking for specialists who can confidently work across frontend, backend, databases, and APIs, design robust application logic, and refine AI-assisted output into production-ready products. Strong problem-solving skills, attention to detail, and the ability to independently architect and ship complete features are essential - Strong command of JavaScript/TypeScript and at least one modern frontend framework (React, Next.js, Vue, Svelte, or similar) - Solid backend experience in Python (FastAPI, Flask, Django) and/or Node.js (Express, NestJS) - Hands-on experience with relational databases (PostgreSQL, MySQL, SQLite) and basic schema design - Experience implementing REST APIs, request validation, error handling, and authentication flows - Familiarity with deployment platforms (Vercel, Netlify, Render, Fly.io , Railway, or similar) - Experience integrating LLM APIs or other AI services into product features is a strong plus - Comfortable with version control (Git) and basic testing practices - Strong attention to detail and commitment to building working, robust products - not demos. - Self-directed work ethic with the ability to architect, build, and ship features independently - Portfolio of shipped web applications (required) - English proficiency: Upper-intermediate (B2) or above (required)

Why this freelance opportunity might be a great fit for you?

- Work fully remote on your own schedule with just a laptop and stable internet connection. - - Gain hands-on experience in a unique hybrid environment where human expertise and AI agents collaborate seamlessly - a distinctive skill set in a rapidly growing field. - Participate in performance-based bonus programs that reward high-quality work and consistent delivery.