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Merge Amazon Seller Central and Walmart Marketplace Sales Data for Inventory Reconciliation

Matching units sold against inventory counts requires the same product and quantity columns across every channel's export.

Why Amazon Seller Central and Walmart Marketplace exports don't line up

Amazon Seller Central: a purchase date/time column stamped in UTC, not your local time; item price, promotion discounts, and Amazon referral fees split across several columns; an Amazon Order ID in a long dashed format (e.g. 123-4567890-1234567). Also, reports differ noticeably between the 'All Orders' report and the Payments/Settlement report — totals rarely match at a glance.
Walmart Marketplace: an Order Date column separate from the ship-by date; item price and a separate Walmart referral fee; a numeric Purchase Order ID. Also, each order line can appear as its own row with a repeated order ID, similar to Shopify's line-item export.

For inventory reconciliation, that mismatch is exactly what causes hours of manual cleanup every period.

Open CSV Experts and set your target columns once (Date, Channel, Order ID, Total).
Drop in your Amazon Seller Central export and map its columns once.
Drop in your Walmart Marketplace export and map it the same way — both merge into one sheet, normalized.
Export as CSV or Excel. Same-layout files merge automatically next time.

No. Everything runs in your browser using JavaScript — your files are never sent to a server.

Yes. Add as many source files as you want; each distinct file layout is mapped once and remembered.