Book a Demo
Sources & Importing

Re-importing & Updating Existing Products

Update your product catalog by re-importing CSV data

On this page

Re-importing & Updating Existing Products

After your initial catalog import, you'll often need to update product data — prices change, new products arrive, vendor information shifts. In Merchkit, you can re-import a CSV to update existing products without creating duplicates.

How Product Matching Works

When you re-import a CSV, Merchkit matches rows to existing products to decide whether to create new products or update existing ones.

Matching by Identifier

Merchkit uses your product identifier field (usually SKU) to find matches:

  • If a CSV row has an SKU that matches an existing product → Merchkit updates that product
  • If a CSV row has a new SKU → Merchkit creates a new product (see the toggle below)

You can also match on other unique fields if SKU isn't your identifier. During the import preview, you'll choose which field to use for matching.

[SCREENSHOT: Matching field selection in import preview]

The "Create new Products" Toggle

During the import flow, you'll see a toggle: "Create new Products for CSV rows without a match".

When It's ON

  • CSV rows with new SKUs (no existing match) will create new products
  • Existing products with matching SKUs will be updated
  • This is useful when you're adding new products to your catalog alongside updating existing ones

Use case: You're importing a monthly vendor shipment that includes 50 new SKUs and updates to 100 existing ones.

When It's OFF

  • CSV rows with new SKUs will be skipped (not imported)
  • Only existing products with matching SKUs will be updated
  • This is useful when you want to refresh data on existing products without accidentally creating new ones

Use case: You're importing a price list that should only update existing products; any new SKUs in the file are data errors you want to ignore.

[SCREENSHOT: Create new Products toggle highlighted]

What Happens to Existing Attribute Values

Updated Columns

When a product matches, any columns you mapped in the import will overwrite the existing values.

Example: Your existing product has Price: $25.00. Your CSV row maps Price: $22.99. After re-import, the product's price is $22.99.

Unmapped Columns

Columns in your CSV that you didn't map to any attribute are ignored. Existing product data in those attributes stays unchanged.

Example: Your CSV has a "Warehouse Location" column that you didn't map. The product's existing Warehouse Location attribute (if one exists) is not affected.

Blank/Empty Values

If your CSV contains empty cells for a mapped column:

  • If the product attribute is optional, it may be left blank or untouched
  • If the product attribute is required, Merchkit will flag a validation error

Best practice: Only map columns you want to update. Leave unmapped columns out of the import entirely.

Common Use Cases for Re-importing

Updating Prices

You receive a new price list from your vendor. Re-import with only the SKU and Price columns mapped, with the toggle OFF to update only existing products.

Adding New Products to an Existing Catalog

Your catalog has 1,000 products. You add 200 new SKUs from a new vendor. Re-import with the toggle ON to update the 1,000 existing products and create 200 new ones in a single import.

Refreshing Vendor Data

Your vendors' lead times and MOQ values changed. Re-import just the SKU, Vendor, Lead Time, and MOQ columns to refresh that information across your product catalog.

Syncing with Your Source System

You have a master product database. Each month, export the latest data and re-import it into Merchkit to keep your catalog in sync.

[SCREENSHOT: Re-import workflow with toggle options]

Best Practices for Safe Re-imports

Always Preview Before Importing

  1. Upload your CSV file
  2. Review the preview screen carefully
  3. Check that columns are mapped to the correct attributes
  4. Spot-check a few rows to ensure values look right
  5. Verify the toggle is set correctly (ON or OFF based on your intent)
  6. Only then click Import

Use "Create a new View" to Review Changes

After importing, you can create a filtered view to see what changed:

  1. Go to your Products list
  2. Click + Create a new View
  3. Filter by the columns you updated (e.g., "Last Updated is in the last 24 hours")
  4. Review a sample of updated products to confirm the import worked correctly

[SCREENSHOT: Filtered view showing recently updated products]

Start with a Test Import

If you're importing a large dataset:

  1. Extract a small sample of 10-20 rows from your CSV
  2. Run a test import with those rows
  3. Preview the results and confirm the update worked as expected
  4. Then import the full file

Keep a Backup

Before importing a large batch of updates:

  1. Export your current product catalog (if possible)
  2. Save it as a backup
  3. Then run the import

If something goes wrong, you'll have the original data to reference.

Common Re-import Issues

"This will overwrite existing data"

Merchkit shows this warning because matched products will be updated. This is expected behavior. Review the preview and confirm the toggle setting before proceeding.

"Duplicate identifiers in the CSV"

Your CSV file contains two rows with the same SKU. This creates ambiguity — which row should update the product? Fix this by removing duplicates from your CSV, then re-import.

"0 products matched"

No rows in your CSV matched existing products. Possible causes:

  • Toggle is ON but all SKUs are new → This will create new products (if that's your intent, proceed)
  • Toggle is OFF but all SKUs are new → No products will be imported; adjust the toggle if you want to create new products
  • SKU values don't match → Check that your CSV SKUs exactly match the SKUs in Merchkit (case-sensitive, no extra spaces)

"Some columns weren't mapped"

You have columns in your CSV that you didn't map to attributes. This is okay — those columns will simply be ignored. If you want to import that data, cancel the import, create the corresponding attribute, and re-import.

Validation Errors During Re-import

If you encounter validation errors during a re-import, refer to Import Validation: Understanding Errors & Warnings for troubleshooting steps.

Next Steps

Your products are in Merchkit and you can keep them up to date with re-imports. Next, you'll set up Attributes to tell the AI how to enrich your catalog. Head to Understanding Attributes in Merchkit.

Previous
Import Validation: Understanding Errors & Warnings
Next
Understanding Attributes in Merchkit