Nutrifriz Backend System

Challenge

Modelling a custom Build Your Mix system where customers pick fruits, set per-fruit gram amounts, and must fill a pack exactly — with server-side validation that can't drift from the client

Solution

Built a modular Express API with clean separation between controllers, services, validators, and models — every layer typed end-to-end with TypeScript and Zod

Challenge

Integrating Flutterwave for payment processing, including signature-verified webhooks, order reconciliation, and keeping pending orders consistent between the checkout redirect and the webhook

Solution

Designed the Build Your Mix system with a rule-driven pricing model where the backend enforces min/max fruits, min grams per fruit, and exact total pack grams — the client can't submit an invalid state

Challenge

Enforcing business rules across many domains — verified-purchase-only reviews, manual orders bypassing payment, role-based access on every admin route, and a loyalty ledger that must never double-count

Solution

Integrated Flutterwave with idempotent verification: the webhook and the verify endpoint both call the same markOrderPaid function, which checks current state before mutating — preventing double stock deduction and duplicate confirmations

Challenge

Designing transactional emails that scale to a dozen different triggers (order paid, processing, shipped, delivered, cancelled, refunded, welcome, password reset) without blocking the business operation on email delivery

Solution

Built a point transaction ledger so every crunch-point earn and spend is auditable; the User.crunchPoints field is a cache that recomputes from the ledger

Challenge

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Solution

Implemented the Resend + React Email stack with a safe-send wrapper — email failures log but never roll back the order, status change, or account action

Challenge

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Solution

Enforced RBAC via composable middleware (requireAuth, requireAdmin, requireRole) so every admin route is locked down by default

Challenge

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Solution

Built dynamic journal categories, product categories, and CMS content — all admin-editable, never hardcoded — with slug auto-generation and conflict handling