Migrating tens ofthousands of productsisn't a CSV upload

In short

For a migration with a five-figure catalog, the task sounds simple: export, import, done. In reality, the import was the smallest part. The work came before it: data model, variants, images, extra fields, redirects and the connection to inventory and ERP. And in deciding what doesn't come along at all.

The case

A merchant moved a very large catalog from WooCommerce to Shopify. The data had grown over years: variants maintained inconsistently, information sometimes in fields, sometimes in the text, images without clear assignment. On top of that came fulfillment and ERP, which had to work immediately after the migration.

How we migrate large catalogs

1. Data model first. What's a product, what's a variant, what's an extra field? These decisions are made before the first import, not after.
2. Define the mapping. Every old field gets its destination in Shopify. Variants, images and SKUs are linked cleanly.
3. Clean up. Duplicate items, legacy baggage, discontinued products. We deliberately narrowed the scope instead of carrying over every bit of baggage unchecked.
4. Work with an import tool. At this size, we use specialized import apps that also handle extra fields and images in bulk. A test run first, then the final import.
5. Prepare in parallel. Redirects, tracking and the connection to fulfillment and ERP don't happen after the import, but at the same time. Otherwise the store works on launch day, but operations don't.

Your takeaways

• Product count doesn't describe the effort. Variants, data quality, images and extra fields do.
• Not everything has to come along. A migration is the best moment to leave legacy baggage behind.
• Messy data doesn't get better in a new system. Errors not fixed before the import land one to one in the new store, just harder to find.
• Think about operations too. Shipping, inventory and ERP have to run on day one, not just the homepage.

Got a large catalog and planning a migration? We clarify the data model and integrations first. Only then does the migration begin.