Preflight CSV
Stop spreadsheet apps from breaking your CSVs
Find all the IDs, codes, dates, and other data formats that spreadsheet apps like Excel and Google Sheets can distort. Export a file that protects critical formatting from unwanted changes.
Runs in your browser. Your file is never uploaded.
How it works
Add a CSV file to start.
Add your file
Pick a CSV and delimiter. It stays on your device.
Check it
Scan for leading-zero IDs, long numbers, date-like text, duplicate headers, and delimiter issues.
Review
See exactly which columns Excel or Google Sheets would change.
Export a safe file
XLSX and TSV open cleanly in spreadsheet apps. Annotated CSV keeps the notes.
Want more from Preflight CSV?
Batch checks, larger files, saved rules, and an offline desktop app are on the way.
Contact support Bugs, export issues, or feature requests Open form
Contact support
Tell us about a bug, an export problem, or a feature you'd like. Please don't paste CSV data or anything sensitive. Just describe what happened.
We read every message and follow up by email if needed.