HOW IT WORKS
See the structure
before the import.
取り込む前に構造を確認
選んだ変更だけを別ファイルへ
CSV Preflight reads CSV or TSV data in this browser tab, flags structural issues, and lets you review selected changes before saving a separate copy. No account is required.
01
Stop a broken row
列数が違う行を止める
When a row has too few or too many columns, values can shift into the wrong fields. The checker shows the location and blocks the checked copy instead of adding, deleting, or guessing at cells.
Load this fictional example 架空例を読み込む →Limit: A structurally valid file can still fail a destination app’s own rules.
02
Keep IDs as text
先頭ゼロのIDを保つ
Values such as 00123, long identifiers, and date-like text are read as text. The checker does not silently turn 00123 into 123.
Load this fictional example 架空例を読み込む →Limit: A spreadsheet or import destination can still reformat values after you open or upload the file.
03
Choose duplicate removal
重複行を自分で選んで除く
Complete duplicate rows are shown, but nothing is removed by default. If you choose removal, the first matching row stays and the selected change appears before export.
Load this fictional example 架空例を読み込む →Limit: It compares complete cell values; it does not decide whether two business records mean the same thing.
A VISIBLE CHECKPOINT
Load → inspect → choose → review → save
Use a separate checked copy. The tool reads that generated copy back and compares it with the changes you selected. It does not overwrite your source file. The three example links load only fixed fictional text and never start inspection automatically.
- LoadChoose a CSV or TSV and select UTF-8 or Shift_JIS, paste text, or load a fictional example. ファイルの文字コードを選んで読み込みます。
- InspectReview structure, headers, duplicates, and warnings.
- ChooseSelect only the header edits or exact-duplicate removals you intend.
- ReviewRead the full list of selected changes.
- SaveDownload a separate UTF-8 copy after its CSV values are read back and compared. 元ファイルは変えず UTF-8のコピーを保存します。
PRIVACY & LIMITS
What this tool does not claim
- Files, cell values, headers, and file names are handled in this browser tab. Reloading or clearing removes the current input from the tool, but it does not securely erase browser memory, history, or files you already saved.
- This portable edition makes no application API requests. Static files are served by the chosen host; browser extensions and hosting-provider traffic are outside this claim.
- Usage recording is off. No operation counts or CSV content are sent by this edition. “Save requested” means only that the user clicked the download link; it does not prove a save or import. この版は利用記録を送信しません。「保存要求」はクリックを示すだけです。
- It does not use AI for normal checks and does not promise that every CSV importer, spreadsheet, or business rule will accept the checked copy.
- It does not guess the file encoding or repair ambiguous separators, invalid text, malformed quotes, or inconsistent row widths. If the file cannot be read, choose its encoding and inspect again. Fix any remaining source errors before retrying. 読めない時はUTF-8またはShift_JISを選び直して再検査してください。
- 通常の検査でAIは使わず、推測による自動修正もしません。取り込み先の必須項目・業務ルール・Excelなどの再解釈までは保証しません。