Private CSV Deduplicatorby Startup Mini Factory Privacy

CSV CLEANUP · PRIVATE BY DESIGN

Remove CSV duplicates by the columns that actually matter.

Choose your key columns, review duplicate groups, and decide what to keep. Your CSV stays on your device.

Works locallyNo accountNo uploadMobile friendly

YOUR FILE NEVER LEAVES THIS BROWSER

Clean a CSV file

or try without a file

HOW TO USE

From messy export to clean CSV in four steps

  1. 1
    Choose your CSV

    Select a file or drag it into the tool. It is read by your browser, not sent to us.

  2. 2
    Select key columns

    Choose the columns that together define the same customer, item, event, or record.

  3. 3
    Choose what to keep

    Keep the first row, keep the last row, or remove every member of a duplicate group.

  4. 4
    Review and download

    Inspect the affected rows, then download the cleaned CSV and an optional removal report.

USE CASES

Built for real CSV cleanup decisions

Customer exports

Match on email, account ID, or phone and keep the record you trust.

Transaction history

Match on customer plus item and keep the latest row after sorting your export.

Research datasets

Find repeated papers, participants, or observations without exposing private data.

Marketing lists

Review duplicate contacts before importing them into another platform.

PRIVACY NOTE

Your file stays on your device.

Your files are processed locally in your browser. This tool does not upload, store, or log the contents of your CSV. Closing or refreshing the page clears the working data from the tool.

Do not use any web tool for data when your organization requires an approved internal system.

FREQUENTLY ASKED QUESTIONS

Before you clean your file

Does this support commas, quotes, and line breaks inside fields?

Yes. The parser supports standard quoted CSV fields, doubled quotation marks, embedded commas, and embedded line breaks. Malformed unmatched quotes are reported as an error.

Can I choose more than one matching column?

Yes. A row belongs to the same duplicate group only when every selected key column matches.

How do I keep the newest record?

Sort your CSV by date before loading it, with the newest record first, then choose “Keep the first record.” You can also sort oldest-to-newest and choose “Keep the last record.”

Does the tool change my original file?

No. Your original file remains untouched. The tool creates a new CSV download.

How large can my file be?

The tool recommends files up to 25 MB. The practical limit depends on your device memory and browser. Very large files may work better on a desktop computer.

ABOUT THIS TOOL

A focused utility, not a data upload service.

Private CSV Deduplicator was created by Startup Mini Factory after reviewing public discussions where people needed column-based matching, large-file handling, keep-first or keep-latest behavior, and safer treatment of quoted CSV. Search volume and market size are not claimed.

Related toolsMore privacy-first data utilities will appear here only after real user evidence supports them.