I need a WEB application (NOT a mobile app) for a cashback management platform called “Interscambio”. Important clarifications: This is a WEB platform only It must be responsive, but NOT a mobile app There are NO in-app payments The system does NOT handle money transfers It only calculates and tracks cashback values Cashback payouts are managed externally and only recorded in the system Because of this, I expect: Reasonable development cost Fast delivery timeline Project Overview: The platform manages a cashback ecosystem involving: Clients Companies Sales Advisors Admin (with MFA login) Main features: • User registration with different roles • Admin approval workflow (records move from “Pending” to “Approved”) • Barcode-style unique IDs generation (C******, A******, S******) • B2B and B2C transaction registration • Automatic percentage calculation based on configurable rules • Full transaction tracking and history • Cashback tracking (calculated only, not paid inside the system) • Admin validation of transactions • Accounting summary views • Invoice record management (manual entry by admin) • Excel export functions • Email notifications (SMTP config file required) Technical requirements: Web application only (no mobile app development) PostgreSQL database HTTPS / SSL Role-based access Full audit trail on edits Logical deletion (no physical deletes) Google Maps integration for company search Online contract signature integration (DocuSign or similar) There is NO: Payment gateway integration Financial transaction processing Wallet system Automatic payout logic This is a structured data management platform with calculation logic and admin validation. The full functional analysis document is attached (very detailed specification). Please provide: Estimated total cost Estimated delivery time Suggested tech stack Confirmation you understand this is WEB only and no payment processing is required I am looking for a developer or small team with strong backend logic skills.