How to format CSV for Excel

1) Make headers safe for spreadsheet tools

Excel is sensitive to blank headers and duplicates. Keep one normalized header row with simple names and stable casing.

• Trim header whitespace and remove special punctuation.
• Ensure every column has a unique name.
• Use snake_case or Pascal style consistently.

2) Guard quote and comma handling

If fields contain commas, wrap values in quotes consistently. Keep embedded line breaks controlled or normalized first.

• Strip stray trailing spaces around delimiters.
• Preserve quoted text fields exactly as text.
• Use one output delimiter policy (comma by default).

3) Align dates and number formatting

Set date and number normalization before upload to avoid Excel auto-converting values differently across versions and locales.

4) Validate with edge test rows

• Test one date at timezone boundary and one negative amount before running full file.
• Check for leading zeros in IDs and phone numbers.
• Verify comma-containing text uses consistent quotes in both sample and export.
• Confirm the same export opens reliably on both Windows and macOS clients.

5) Minimal fallback template

If your source is from an unstable template, use this sequence:

1. Normalize headers and remove empty rows.
2. Normalize quotes and delimiter.
3. Set date strategy (`YYYY-MM-DD`) and number strategy (`.` decimal).
4. Run preview, then re-export.