Full-stack Developer - manufacturing projection planning SaaS (multi-Tenant, AI scheduling)

We're looking for a senior full-stack engineer to build ProdPlan, a multi-tenant SaaS platform that helps manufacturers plan and track production against real constraints — customer orders, machine/work-center capacity, raw material availability, and delivery deadlines. It replaces spreadsheet-based planning with a single live production schedule. WHAT IT DOES Planners create orders, the system checks material and capacity availability, builds a day-by-day machine schedule, and gives floor supervisors and managers real-time visibility into production status against every delivery deadline. USER ROLES Admin, Production Planner, Floor Supervisor, Viewer — each with role-based access. CORE FEATURES - Multi-tenant architecture with full data isolation per manufacturing unit - Email/password auth with role-based access control - Order management (create/import orders: product, quantity, priority, deadline) - Machine & work-center master data (capacity, shift calendar, downtime) - Material master & inventory with per-product BOM - Production scheduling engine (capacity + material + deadline-aware sequencing) - Conflict detection (overloaded machines, material shortages, at-risk deadlines) - Visual Gantt-style planning board with drag-to-reschedule - Stage-wise production status tracking (queued/in-progress/on-hold/completed) - Delivery deadline tracking with automatic at-risk/delayed flags - Admin analytics dashboard (utilization, on-time delivery, throughput) - Email + in-app notifications - CSV/PDF report export - Responsive UI for office and floor/tablet use AI & AUTOMATION - AI-assisted schedule optimization (conflict-minimized sequencing) - Material shortage prediction against BOM + stock + lead time - Delivery-risk detection with contributing reason (capacity/material/delay) NON-FUNCTIONAL REQUIREMENTS Encryption in transit/at rest, per-tenant isolation, role-enforced API access, full audit logging, sub-2-second page loads, 99.5%+ uptime target, architecture that scales from a single pilot plant to multiple units. MILESTONES ($2,500 each, 10 days total) Milestone 1: Multi-tenant setup, auth/RBAC, order management, machine & material master data, base admin dashboard, staging deployment. Milestone 2: Scheduling engine, conflict detection, visual planning board, production status tracking, deadline tracking, in-app notifications. Milestone 3: AI scheduling optimization, shortage/delivery-risk prediction, manager analytics dashboard, email notifications, report export, audit logging, security hardening, full production deployment & go-live (domain, hosting, SSL, DB, cutover). DELIVERABLES Fully working, tested, production-deployed platform with source code, environment setup docs, and a handover/knowledge-transfer session. WHO WE'RE LOOKING FOR - 5+ years full-stack experience, proven SaaS/multi-tenant project history - Strong with a modern JS/TS stack (React/Next.js + Node or similar), Postgres or similar relational DB - Comfortable owning scheduling/constraint-based logic, not just CRUD - Experience integrating AI/LLM features into a product - Can work independently to a fixed 10-day, 3-milestone timeline - Handles own deployment (domain, hosting, SSL, DB) end-to-end Please share 1-2 examples of SaaS or scheduling/planning tools you've built, and briefly outline your approach to the scheduling engine before we move forward.