Fashion, footwear, and apparel retail lives and dies by the size/color grid. A single style ships in dozens of variants, and ERPNext models each one as a distinct Item Variant under an Item Template with has_variants and its own Item Attributes. That data model is correct, but the native UI was never designed for a merchandiser thinking in matrices: adding a new season means creating variants one at a time, receiving stock means hunting through a flat item list, and the standard POS Awesomebar makes a cashier type to disambiguate "black / M" from "black / L" mid-queue. ERPNext core gives you the ledger; it does not give you the grid. That gap is where apparel retailers stall, resort to spreadsheets, or mis-count inventory at the variant level.

We build a proper Frappe app — a versioned, bench get-app-installable module, not a pile of customizations — that layers matrix merchandising and a fashion POS on top of your existing ERPNext without forking core. The heart is a size/color matrix grid: a client-scripted UI where a merchandiser picks a Style/Item Template and enters quantities, prices, or barcodes across a rows-by-columns grid (for example size down the side, color across the top), and a whitelisted server method (frappe.whitelist()) fans that grid out into the correct Item Variants, Item Barcodes, and stock or price rows in one transaction. Barcode-per-variant generation is wired through a hooks.py doc event so every variant that comes into existence gets a scannable code (EAN-13 / Code128) attached to its Item Barcode child table, and the POS is extended so a scan resolves straight to the exact variant line — no cashier lookup. A Matrix Stock View DocType and Query Report roll Bin quantities back up into the same grid across every Warehouse/store, so a buyer sees the full size curve per store at a glance and spots the broken sizes before they become markdowns. Season/collection and style attributes are added as custom fields and a Collection DocType so you can merchandise, filter, and report by season the way the industry actually works.

Everything is built to ERPNext conventions so it survives upgrades and audits: real DocTypes with fixtures, Server Scripts and app hooks rather than hand-edits, Client Scripts for the grid UX, permissions expressed through Role Profiles and DocType permissions (a cashier role sees POS, a merchandiser role sees the matrix, a buyer sees the stock view), and Scheduler Events for any nightly reconciliation such as re-syncing barcodes or flagging negative variant stock. The matrix grid and stock view are also reachable over the Frappe REST API and custom whitelisted endpoints, so a Shopify/marketplace connector or a mobile stock-count tool can read and write the same variant data. It targets Frappe/ERPNext v15 and v16.

Because this is build-to-order, nothing here is a one-click marketplace download. After a short scoping call we confirm your exact attribute structure (your real size runs, color libraries, and season taxonomy), your store/warehouse layout, and your POS workflow, then quote a fixed scope. We build on a staging bench, hand you the code for User Acceptance Testing, and — on your sign-off — install into production with a documented rollback path. Typical delivery is one working week from confirmed scope, depending on how many attributes, stores, and integrations are in play. You receive the source, the git repository, technical and user documentation, a training session, and a post-go-live support window.