ERPNext ships with the Shipping Rule DocType, but it only knows a single condition axis: it matches an order total (or net weight) against a band and applies one charge. It cannot layer zone, weight and cart value together, it has no concept of a free-shipping threshold that varies by region, it does not model dimensional (volumetric) weight, and it applies the same logic to every sales channel and customer group. Webshop merchants running real fulfilment quickly hit that ceiling: a flat rule that is fair for a light, local order overcharges a bulky remote one, or silently loses margin on the reverse. Teams end up hand-editing Sales Taxes and Charges rows or maintaining a spreadsheet of postage bands outside ERPNext, which is exactly the kind of manual, error-prone work an ERP is supposed to remove.

We build a proper Frappe app (its own module, installable via bench get-app / bench install-app) that adds a real rating engine on top of ERPNext. The core is a set of new DocTypes: a Shipping Zone mapping countries, states and pincode/postcode ranges to a zone; a Shipping Method (standard, express, pickup, courier account); and a Zone Rate Table with child rows expressing tiered pricing by weight break, order value break and quantity, plus flat-rate and free-shipping-threshold fields per zone and per method. Rates are resolved at quote/order time by a whitelisted server-side method that reads the cart's destination address, computes billable weight as max(actual_weight, volumetric_weight) from item dimensions, selects the matching zone and tier, and returns the applicable methods with prices. Because rate selection lives in server script logic wired through hooks.py doc events (validate / before_save on Quotation and Sales Order) and a whitelisted API endpoint, the same numbers are returned whether the request comes from the ERPNext Webshop, the desk, or an external storefront calling the Frappe REST API.

On top of the engine we build the operational layer your team actually touches: a rule-priority resolver so per-customer-group and per-channel overrides beat the default zone rate deterministically; role-based permissions and a role profile so shipping managers can edit rate tables without touching accounting; client scripts on the sales form that show the live-calculated shipping options and let a CSR override with a logged reason; and optional scheduler events (via scheduler_events in hooks.py) to refresh carrier fuel/surcharge factors or expire seasonal free-shipping campaigns automatically. Everything is delivered as versioned source in a git repository, targeting Frappe/ERPNext v15 with a v16 compatibility path, so it survives bench update rather than being a fragile in-desk customization.

Because this is a build-to-order product, nothing is a black-box download. We start with a short scoping call to capture your zones, carriers, weight/dimension data quality, channels and the exact free-shipping rules you want, then we build against that specification, demonstrate it on a staging bench for UAT, and only cut over to production once you sign off. Typical delivery is one working week from confirmed scope depending on how many zones, carriers and channel-specific rules are involved. You receive the full source, install and configuration, documentation, a training session and a post-go-live support window — you own the code and can extend it yourself or have us maintain it.