Mastron Express — Parcel & Courier System

Overview

Complete courier operation: parcel creation, tracking and status events, merchant and delivery‑man portals, live GPS tracking with route optimization, COD and financial reports, SMS through multiple providers, and a JWT mobile API.

01The challenge

A shipping company serves three parties with different needs: the merchant wants to upload shipments and follow their collections, the courier wants today’s list and a fast way to prove delivery, and the operator wants to know where every parcel and every pound is.

Money is the hardest part: the courier collects cash on the merchant’s behalf, so the amount passes through three ledgers before it settles — courier, company, merchant — and any undocumented link means an unexplainable gap at month end.

On top of that, couriers work in areas where the network drops, so delivery cannot stop because the signal is weak.

02What we built

A parcel is an entity with a full event log: every barcode scan, status change and delivery attempt is a timestamped row, so tracking is derived from the log rather than overwritten on the previous state. Delivery is proven with a signature, a photo and a scan — not a button press.

The financial side runs on explicit accounts: one for the courier, one for the merchant, one for the company, with documented transfers between them, plus batched payouts, COD charges and defined additional fees. Every pound has a source and a destination.

Pricing was built as rules rather than a fixed table: one rule by weight, one by size, one by package and area — so changing pricing policy is configuration, not a code change.

And because the network drops, the courier app has a sync path (sync batches and sync operations) that queues work locally and uploads it when the connection returns.

03The outcome

Merchants follow their own shipments and collections instead of calling support, and operators read a parcel’s state from its event log rather than from someone’s memory.

Settlement closes: every collected amount appears in the courier’s account, then in a transfer, then in the merchant’s payout — with no missing link.

Network loss no longer stops work: the courier delivers, signs and photographs, and the operations upload themselves when the signal returns.