Full Stack + AI Engineer - Feature Work on Existing Product (Paid Skill Test, Ongoing Potential)

We’re building a full stack product with AI features and looking for a reliable developer who can work inside an existing codebase, ship clean features quickly, and communicate well. This post is for a larger / ongoing collaboration. To start, we’ll begin with a paid skill-test task (4–6 hours) so both sides can evaluate fit before committing to more work. About the product (broader context) We’re developing a web application that combines: Full stack web development (frontend + backend/API) AI/LLM features (chatbots, assistants, summarization, workflow automation, etc.) Iterative feature delivery on a live/existing codebase If the test goes well, follow-up work may include additional AI modules, API integrations, UI improvements, and product iterations. Paid skill test (first milestone) You’ll receive access to our existing repo and implement the features below. This is not a greenfield build. Work inside the current stack and follow existing patterns. Features to add in the test (required) AI chatbot UI Simple chat interface (message input + response list) Loading state while waiting for AI response Disable send button during loading Backend AI endpoint Create/update POST /api/ask (or equivalent) Accept user message and return AI reply as JSON OpenAI (or similar LLM) integration Use gpt-4o-mini (or equivalent cost-efficient model) Read API key from environment variables Include .env.example (no real keys in repo) Context-based chatbot replies Use provided content/knowledge file as context Chatbot replies should stay relevant to that content Fallback handling If the question is outside scope, return a polite fallback message Handle empty input, missing API key, and failed requests gracefully End-to-end wiring Connect chatbot UI to backend endpoint Feature must work locally with clear run instructions Delivery quality Clean, readable code matching existing style Short README notes: what changed, how to run, how to test One small revision round after review Out of scope for this test Auth / login Database Payments Admin dashboard Mobile app Large refactor of existing architecture Expected stack (flexible) Frontend: React / Next.js Backend: Node.js / Express or Next.js API routes AI: OpenAI (or similar LLM API) GitHub-based workflow (PR delivery) Deliverables Working AI chatbot features listed above in the existing repo Clean PR or zip with clear commits .env.example + setup notes One short revision round Timeline & budget 4–6 hours Fixed paid test milestone Successful freelancers may be invited to ongoing / larger project work What we’re evaluating Ability to work in an existing codebase Practical AI chatbot integration skill Code quality and attention to detail Communication and on-time delivery Please include in your proposal Relevant full stack + AI experience Confirmation you can complete this test in 4–6 hours Your preferred stack Availability for ongoing work if selected 1–2 similar projects (links preferred) Important Please only apply if you’re comfortable starting with a small paid skill test before larger collaboration. Strong performers will be considered for continued project work. Looking forward to working together