Data Anonymizer
Mask or replace PII in CSV files. Replace names, emails, and phone numbers with anonymised values. The safest way to process
Your files never leave your device. Processed locally. 100% private.
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How To Use Data Anonymizer
Complete your task perfectly in just three straightforward steps.
Upload CSV
Drop your CSV file containing PII.
Select columns to anonymize
Choose which columns to mask — name, email, phone, address, etc.
Download
Download the anonymized CSV.
FAQ
Everything you need to know about the Data Anonymizer.
What anonymization methods are used?
Masking (e.g. J*** D***), pseudonymization (fake but consistent replacements), and full redaction.
Is the mapping reversible?
Pseudonymized data uses a consistent hash — the same value always maps to the same pseudonym within a session.
Is my file uploaded?
No. Everything runs locally in your browser.
What is the file size limit?
Process files up to the browser memory limit.
Can I preview before downloading?
Yes — a before/after preview shows the first 20 rows.
Is this tool GDPR compliant?
The tool produces pseudonymized data as defined in GDPR Article 4(5): data that can no longer be attributed to a specific person without additional information. Pseudonymized data still qualifies as personal data under GDPR if re-identification is possible (e.g., if you keep a mapping table). For fully anonymous data that falls outside GDPR scope entirely, use the Address and Name strategies in combination and avoid the Hash strategy, since the hash is deterministic and could be reversed if the original values are known.
Can I anonymize Excel files?
Yes. The tool accepts .xlsx and .xls files in addition to .csv. Excel files are read using SheetJS — the first sheet is loaded and processed. The output is always a CSV file. If you need the result as Excel, use the CSV to Excel converter tool after anonymizing.
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