Catch broken CSV deliveries before they break your workflow.

02 · REUSABLE WORKFLOW

Recurring CSV Drift Check Pack

Save the structure of a known-good CSV locally, then compare each later delivery for added, missing, or reordered columns before it reaches a downstream import. The pack is a small Python 3.10+ standard-library tool with a concise operating guide; it contains no upload or networking code. It is intentionally focused on repeatable structural preflight rather than type inference, nullability, sparsity, or broad data-contract governance.

• Save a reusable structural baseline from a known-good CSV.
• Refuse structurally broken files as a baseline before they become the reference.
• Detect added, missing, reordered, duplicated, or blank column names.
• Detect row-width mismatches before recurring imports run.
• Use deterministic exit codes and optional JSON reports in scheduled jobs.
• Run locally with Python 3.10+ and no third-party packages, account, or file upload.

Best fit: operators or back-office teams that repeatedly receive CSV exports or vendor files and want a small local preflight step before import.

Skip this pack if: your existing schema, data-contract, or pipeline tooling already catches the structural changes you care about. This pack is not broader or more advanced than those tools.

Delivery model: after payment, Square redirects to an unlisted shared download page. Delivery is not tied to a purchaser account, so keep the download URL private. For the USD checkout, Gumroad delivers the same pack through Gumroad. Neither option is a subscription.

See the exact report shape before buying. If a known-good file has order_id,total and a later delivery adds currency, the checker exits with code 3 and reports added_headers: ["currency"]. View the complete sample JSON report.

Ready to use it? JPY checkout: ¥2,980 via Square. USD checkout: USD 29 via Gumroad. Both are one-time purchases of the same pack. Seller disclosure / 特定商取引法に基づく表記

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Running a recurring import? Read the free CSV import preflight checklist and use the browser checker above before deciding whether you need the reusable pack.