Shelf answers the three questions every equipment manager dreads — who has it, where is it, and when is it coming back — using QR-code-first tracking where every asset gets a unique scannable label, every handover is logged with timestamps and e-signed custody agreements, and every scan captures GPS coordinates displayed on a map. Built on React Router 7 with React 19, TypeScript 5, Prisma 6 ORM, and Tailwind CSS 3 with Radix UI components, the platform generates QR codes and barcodes (Code128, Code39, Datamatrix) printable on DYMO, Brother, and Zebra label printers. The custody system records every handover with user details and generates PDF custody agreements with e-signatures for high-value items, while a complete audit trail tracks responsibility from check-out to return. The visual booking calendar prevents double-bookings automatically, supports partial check-outs and returns with segmented lifecycle bars, and handles quantity-tracked consumables alongside individually serialized equipment. Asset Models enable bulk creation of identical items with shared defaults while maintaining individual QR codes and custody histories. Location tracking displays last-scanned GPS coordinates on MapTiler maps. Supabase Auth provides email and SSO authentication, pg-boss handles background job queuing, and Nodemailer delivers SMTP email. The Shelf Companion app on iOS and Android enables field scanning and bookings. Export Asset Inventory, Asset Distribution, and Custody Snapshot reports for compliance. Deploy via Docker with PostgreSQL and Supabase. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL v3.0 licensed.