Build our AI platform V1 (specs + React UI code ready): RAG & LLM agents, NestJS - 8-12k EUR

I am the founder of an early-stage startup building an AI platform for French industrial SMEs. I run the project myself: it is lean, fully specified and ready to build. I am looking for a developer to build the V1 with me, and to keep growing the product with me after launch. The platform has two parts: a client application (conversational assistants, automated agents for quotes, purchase orders, unpaid invoices and stock alerts, with two roles: admin and employee) and an internal back office to run the platform (customer accounts, agent catalogue, monitoring, read-only support access). In V1, business data comes from Excel/CSV files uploaded by the customer: no ERP integration yet. What is already done, so you can focus on building: - Detailed functional and technical specifications, available in English. Most decisions are already made and written down, so there is little to design or decide: the work is mainly building. Of course, some challenges will come up along the way; questions are answered quickly, in writing. - A working, clickable React prototype covering the screens and user flows. Its UI code can be reused wherever it saves time. - The visual style already set in the prototype: colours, typography and components. - An accessibility document (WCAG 2.1 AA is mandatory) - The infrastructure accounts, opened and paid by my company: AWS (including Bedrock for the AI models), hosting in France and a GitHub organisation. You get your own access from day one. The work: - V1 split into 6 Lots, built in a fixed order - Budget: 8,000 to 12,000 EUR for the V1 - Target: about 3 months for the V1, working close to full time - You send me your quote: a fixed price and a target date for each Lot, set by you - Automated tests included in every Lot (quotes "without tests" are not considered) - 4 AI agents in V1 - Stack: React + Vite, NestJS, PostgreSQL - GDPR by design: personal-data vault, immutable legal log, multi-tenant isolation Profile: - Solid full-stack experience, ideally across different kinds of projects - Hands-on experience shipping LLM features in production: RAG (embeddings, vector search with pgvector, chunking, citations), tool / function calling, structured outputs, and prompt design - Committed to delivering a project end to end, carefully and with tests - Comfortable reading detailed specifications in English - Using AI coding tools (for example Claude Code) in your daily work is a strong plus How we will work together: - Each Lot is paid at the price you quoted, after acceptance, through Upwork - 100% of the code belongs to my company, pushed daily to its GitHub - You never access real personal data (fictitious test data only) - A short written status every Friday - A long-term relationship: 15 more agents and ERP connectors (Sage, Cegid, SAP) are on the roadmap - After launch: a 1-month warranty starting with the first real customer (at the latest 3 months after delivery), then optional paid support if we both want it To apply, please answer the screening questions, and in your cover letter tell me about a project you are proud of (your role, and how you used AI coding tools), with a link to your GitHub or portfolio. Shortlisted candidates will sign an NDA, then receive the full specifications and the draft contract to prepare a detailed quote within 5 days. I would like to start as soon as possible.