A complex catalog migration inventories products, variants, attributes, bundles, pricing rules, media, and content assets—with field-level mapping and diff reporting before anything touches production. Custom Magento modules and third-party extensions are mapped to Shopify-native patterns, apps, or middleware—not copied blindly. Integrations to ERP, OMS, tax, and marketing systems get new API contracts on Shopify, with retries and reconciliation when systems disagree. SEO work, customer and order history retention, and cutover rehearsal run in parallel with catalog jobs so launch is a controlled program—not a theme swap followed by firefighting.