Check your product CSV before Shopify rejects it.
Drop in the product CSV you are about to import. You get a row-by-row list of what breaks Shopify's published rules: missing titles, bad handles, wrong true/false values, price formats, duplicate option sets, over-long SEO fields and more. Nothing is uploaded.
Built from Shopify's product CSV guide and its list of import errors, and tested on Shopify's own template file. It is not Shopify, and passing here does not guarantee the import: Shopify checks more than this tool can, and image links are not opened. Make a copy of your file before you edit it. Your products are not read by anyone but your browser.
Shopify says to save the file as UTF-8. One file at a time, up to 40 MB.
What it checks
Title and handle, status of active, draft or archived, true or false fields, and products that repeat a handle in separate blocks.
Duplicate option sets, price and weight formats, inventory fields, packed size columns and fulfillment service.
Tag, barcode, SEO and image limits, and image links that are not https.
Questions
Which columns does it understand?
Both the current column names in Shopify's template (for example URL handle, Status, Charge tax) and the older names (Handle, Variant Price, Variant Grams). Columns it does not know, such as metafields, are listed and left unchecked.
What is the difference between new and update mode?
Shopify says Title is required when you add products, and URL handle is required when you add variants or update products. The mode changes the message for a missing handle column.
Why are some findings warnings?
Where Shopify's guide only lists example values or gives a default, the finding is a warning, not an error. Inventory tracker is one example.