Anonymize CSV Data, free in your browser

Replace values in selected CSV or TSV columns with consistent pseudonyms. Repeated values receive the same replacement within each column, while blank cells, headers, and unselected columns stay unchanged.

How to anonymize CSV data

1. Choose a CSV or TSV file.
2. Select each column containing names or other values you want to replace.
3. Anonymize and download the new CSV copy.

Limits & good to know

• Files up to 50 MB, 500,000 rows, and 2,000 columns are processed locally in your browser.
• Pseudonyms preserve repeated-value relationships within each column; they are not cryptographic tokens and should not be treated as irreversible anonymization.
• The source file is unchanged; download a separate anonymized copy and review it before sharing.

Frequently asked questions

Are my files uploaded to a server?

Your files are processed on your device, not uploaded to our servers. Your file and edits are saved in this browser for recovery, and previous documents remain in Saved drafts when you open another file. Use Saved drafts to resume or delete individual copies, or clear this site’s browser data to remove all copies. Browser storage can be cleared or become unavailable; download important work.

Will the same value get the same pseudonym?

Yes. Within each selected column, matching values get the same pseudonym. The same value in different columns is mapped separately.

Does this securely anonymize the entire file?

No. It only replaces values in the columns you select. Review other fields for identifying details before sharing.

Is this really free, or free "until you hit a limit"?

Really free. Unlike most "free" PDF sites there is no task-per-day cap, no locked Pro features, no watermark stamped on your file, and no payment step before download. Every tool is the full tool.