Shipping, logistics & API engineering
Guides and deep dives on shipping rate calculation, pincode data and courier logistics for Indian ecommerce — written by the team building Postpin.
Shipping Webhooks: Automate Your Logistics Stack with Real-Time Events
Polling APIs for changes wastes quota and reacts late. Webhooks push events — rate calculations, key changes, billing updates — to your systems in real time. Architecture, security (HMAC) and retry handling explained.
Hidden Courier Charges Decoded: Fuel, Remote Fees, Minimums and GST
The freight rate is just the sticker price. Fuel surcharge (~12%), remote-area fees, minimum charges and 18% GST decide what you actually pay. Decode every line of an Indian courier invoice.
Surface, Air, Express or Same-Day? Choosing Courier Service Levels
Air costs ~1.4× surface, express ~1.6×, same-day ~2.8×. Multipliers make service levels easy to price — the hard part is knowing when the upgrade earns its cost. A practical guide for Indian shippers.
Flat-Rate vs Real-Time Shipping: What Should Your D2C Store Charge?
Flat shipping is simple but silently redistributes money — from your margin and your nearby customers to your farthest lanes. Real-time rates are accurate but noisier. Here is a framework for choosing, with a hybrid most stores should steal.
Integrating a Shipping Rate API in Node.js: The Complete Walkthrough
From API key to live checkout quotes in under an hour: authentication, your first rate call, serviceability checks, error handling, caching and going live — with copy-paste Node.js examples throughout.
Shipping Costs Cause Most Cart Abandonment. Here's How to Fix Yours
Unexpected shipping cost at the last step is the single biggest reason Indian shoppers abandon carts. The fix is not free shipping — it is early, accurate, honest shipping. Five tactics that measurably recover checkouts.
The India Post Pincode Directory: A Practical Guide for Developers
All Indian logistics runs on one dataset: the India Post pincode directory — 165,000+ post offices collapsing into 19,000+ delivery pincodes. Here is how the system works, where to get the data, and why it goes stale fast.
Pincode Serviceability: Why Every Indian Checkout Needs the Check
"Do you deliver to my pincode?" is the first question Indian shoppers ask. A serviceability check answers it in milliseconds, prevents failed orders, and unlocks smarter COD and SLA decisions. Here is how to build it.
Cash on Delivery in India: What COD Really Costs Your Store
COD still drives a huge share of Indian ecommerce — but it is not free. Between flat fees, percentage charges and RTO risk, COD economics can quietly erase margins. Here is the full cost breakdown and how to price it.
Shipping Zones in India: Within City, State, Metro and Beyond
Couriers price India as five lanes, not thousands of city pairs. Understand within-city, within-state, metro-to-metro, rest-of-India and special zones — and why the same box costs ₹75 or ₹220 depending on the lane.
Volumetric Weight Explained: Why Your 1 kg Parcel Is Billed as 5 kg
Couriers charge for space, not just mass. Volumetric (dimensional) weight is why light-but-bulky parcels cost more than you expect. Here is the exact formula Indian couriers use, with examples and packaging tips.
How to Calculate Shipping Charges Between Indian Pincodes (2026 Guide)
Shipping charges in India are driven by five inputs: origin pincode, destination pincode, chargeable weight, service level and payment mode. Here is exactly how couriers compute a quote — and how to automate it.