PREFLIGHT CHECK

Mercari Shops product CSV preflight checker

Check encoding, headers, length limits, spaces and required values before importing a Mercari Shops product CSV.

Check CSV

🔒 Analysis runs in your browser. The CSV file itself is not uploaded to BlueprintLab.

What this tool checks

  • CSV structure and encoding
  • 130-character product name / 3,000-character description limits
  • Half-width spaces outside name and description
  • Common required status and shipping fields
  • Basic image name / URL format

What this tool cannot verify

The tool does not claim to verify live service-side master data, account-specific state, or network reachability that cannot be established reliably in-browser. The service’s own validation remains authoritative.

How to use this tool

Check encoding, headers, length limits, spaces and required values before importing a Mercari Shops product CSV.

  1. Use Try sample to inspect the included sample.
  2. Set + Choose a CSV file Tap or click to choose. Drag & drop also works on desktop..
  3. Use Check CSV to process the input.
  4. Compare the result with your source data and return to the input to make corrections.
+ Choose a CSV file Tap or click to choose. Drag & drop also works on desktop.
.csv,text/csv

Input and settings example

商品名,商品説明,商品の状態,配送方法,発送元の地域,発送までの日数,商品ステータス,商品画像名
サンプル商品,説明文,1,1,13,2,1,https://example.com/item.jpg

When this tool helps

Use this after preparing a Mercari Shops bulk product CSV to catch missing core headers before upload. It looks for fields such as product name, SKU1 stock, condition, selling price, shipping method, ship-from region, and handling time, then checks row-level values.

Column order can change, but required business fields cannot simply disappear. A missing column and a blank cell are different problems, so the checker reports them separately.

Product name is only one layer

Mercari Shops also documents value-level rules such as the 130-character product-name limit and 3,000-character description limit. Half-width spaces outside product name and description can also be a documented import-error cause.

The browser cannot verify live brand/category master IDs or prove that every remote image URL is reachable. Those remain management-screen checks.

Separate template problems from row problems

If a required header is missing, rebuilding from the current official format is usually faster than fixing rows one by one. If the headers are present and only a few rows are flagged, focus on those rows’ blank values, lengths, and spaces.

If you edited the CSV in Excel, separately protect identifiers such as management codes and JAN values from automatic numeric conversion.

A practical workflow

For a 1,000-product upload, first create a 5–10-product sample that includes representative products and variants. Run the checker, perform a real bulk upload, inspect the management screen, and only then expand the same structure to the full catalog.

Bulk import saves time, but it also scales mistakes. A small end-to-end test is the cheapest place to catch them.