google-merchant-feed

Overview

This skill guides the creation of a valid Google Merchant Center product feed (XML/RSS 2.0) from any backend stack. It encodes lessons learned from production implementations and Google's official specification.

Supported backends:

• Django / Python (ElementTree or lxml)
• Node.js / Express (xmlbuilder2)
• Next.js API Routes (App Router or Pages Router)

When to Use

• User wants to create a Google Merchant / Google Shopping product feed
• User has a feed that Google Merchant Center rejects with validation errors
• User asks about g:availability, g:price, g:gtin, g:google_product_category
• User needs to expose products to Google Shopping ads
• User asks "how do I send products to Google?"

Instructions

Step 1 — Identify the backend

Ask or detect which backend the user is working with:

• Django/Python → load references/django-python.md
• Node.js/Express → load references/nodejs.md
• Next.js → load references/nextjs.md

Step 2 — Load requirements first

Always read references/google-requirements.md before any implementation. It contains field-by-field validation rules that apply to all backends.

Step 3 — Apply the complete checklist

Before delivering any implementation, verify against this checklist:

Queryset / data source:

• Filter is_active=True (or equivalent)
• Exclude products with empty name
• Exclude products with price <= 0
• Exclude products with null or empty slug/URL
• Limit to a safe maximum (5000 items) to avoid memory issues

Required fields — all must be present and non-empty:

• g:id — stable unique identifier
• g:title — Title Case, max 150 chars, no HTML
• g:description — max 5000 chars, fallback to title if empty
• g:link — absolute HTTPS URL using the canonical frontend domain
• g:image_link — absolute HTTPS URL; fallback to default image if empty, never empty string
• g:availability — exactly in stock or out of stock
• g:price — format {number:.2f} {ISO-currency} e.g. 1500.00 ARS
• g:condition — exactly new, used, or refurbished

Recommended fields:

• g:brand — only if present, skip if null
• g:gtin — validate: numeric only, length in (8, 12, 13, 14); skip if invalid
• g:mpn — product code/SKU
• g:google_product_category — numeric ID from Google taxonomy
• g:product_type — local category name

Channel metadata:

• <link> points to the frontend domain (not the API domain)
• xmlns:g="http://base.google.com/ns/1.0" namespace present
• Content-Type: application/xml

Common pitfalls to avoid:

• g:image_link with empty string — Google rejects it; always use a fallback image URL
• g:gtin with "0", "000000000" or non-numeric strings — validate strictly
• Titles in ALL CAPS — normalize to Title Case with .title() or equivalent
• g:link pointing to the API domain instead of the frontend
• g:sale_price with same value as g:price — only emit if actually different
• Hardcoded domain strings — use a config variable for the frontend URL

Reference Files

File	Content
references/google-requirements.md	Full field spec, validation rules, Google taxonomy tips
references/django-python.md	Complete Django view using ElementTree
references/nodejs.md	Express route using xmlbuilder2
references/nextjs.md	Next.js App Router API route