Full-Stack Developer for SaaS MVP

I am looking for an experienced full-stack developer to build the first working MVP of FLoW, an AI-assisted compliance and tender-readiness SaaS platform initially designed for UK electrical contractors. The product concept, core user journey, screen flow and MVP requirements have already been developed. A detailed Developer Handover Specification is available. The MVP will include: User authentication and company onboarding Company profile and applicability questionnaire A rule-based Requirements Engine Compliance dashboard and requirements matrix Secure document upload and storage AI-assisted document classification and structured data extraction Human review and correction of AI-extracted information Document library and expiry tracking Tender/PQQ document upload and AI-assisted requirements extraction Matching tender requirements against existing company evidence Transparent readiness scoring Prioritised action plans Requirement-level guidance Basic people/responsibility records Reporting views The preferred technical approach should use a modern, maintainable SaaS stack. Relevant experience may include React/Next.js, Node.js or a suitable backend framework, PostgreSQL/Supabase or equivalent, secure cloud document storage, API integration, OCR/document processing and AI/LLM integration. I am particularly interested in developers who have previously built real SaaS products, AI-enabled applications, document-processing systems or business workflow platforms. The project is a fixed-price MVP with an estimated maximum budget of $6,000 USD. I want the work delivered through clear milestones with payments linked to completed and accepted deliverables. The objective is not to build an unnecessarily large enterprise platform at this stage. The goal is to build the smallest credible working version of FLoW that completes the full user journey and can be tested with real users. It is important that: The client has administrator access to the source-code repository. The application is built using client-controlled or client-accessible hosting, database and service accounts. All bespoke code produced and paid for under the project is transferred to the client, subject to clearly disclosed third-party or open-source components. AI outputs are reviewable and the system does not silently invent missing compliance data. The application is built on a foundation that can be expanded after MVP validation. Please include in your proposal: Examples of relevant SaaS or AI applications you have personally built. Your proposed technology stack. How you would approach the Requirements Engine and AI document-processing workflow. Your proposed milestones and delivery timeline. What you can realistically deliver within the stated budget. Any third-party services and estimated ongoing costs. Your testing and post-launch bug-fix arrangements. Please do not send a generic proposal. Briefly explain how you would approach FLoW based on the requirements above.