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CSV Deduplicator error
⌃⏎ run · ⎋ clear · / focus input
// about this tool

CSV Deduplicator Online

Updated 2026-08-19

Remove duplicate rows from a CSV instantly, right in your browser. Paste your data and SnapTools returns a clean, de-duplicated CSV as you type — match on every column or pick a single key column, keep the header, and preserve the first occurrence of each row. Nothing is uploaded: the work runs locally, so it is safe for private spreadsheets and exports.

Duplicate records creep into merged exports and mailing lists and are tedious to find by hand. The CSV Deduplicator collapses them in one step — whether you are cleaning a contact list, merging files, or preparing a unique data set for analysis.

// how to use

  1. 1 Paste or type your CSV into the input panel on the left — duplicates are removed as you type.
  2. 2 Open Settings to pick the delimiter (comma, tab, semicolon, or pipe) and choose whether to match on all columns or one key column.
  3. 3 Read the de-duplicated CSV on the right, with the header preserved and the first occurrence of each row kept.
  4. 4 Click Copy or Download to save the result.

// examples

Remove fully duplicate rows
Input
id,name
1,Ada
2,Linus
1,Ada
Output
id,name
1,Ada
2,Linus
De-duplicate by a key column
Input
email,plan
ada@x.com,pro
linus@x.com,free
ada@x.com,team
Output
email,plan
ada@x.com,pro
linus@x.com,free

// common uses

Cleaning a mailing list before import Removing repeated rows from merged exports Collapsing duplicate records by an id or email Preparing a unique data set for analysis

// faq

Is my CSV uploaded to de-duplicate it?
No. The de-duplication runs in your browser — nothing is uploaded, so it is safe for private spreadsheets and exports.
Which copy of a duplicate is kept?
The first occurrence of each row is kept and later duplicates are removed, so the original order of unique rows is preserved.
Can I de-duplicate by a single column instead of the whole row?
Yes. In Settings, choose a key column to treat rows as duplicates when that column matches, even if other fields differ.
What is the difference between CSV Deduplicator and CSV Diff?
The deduplicator removes repeated rows within one file. CSV Diff compares two separate files to show added, removed, and changed rows.
Is the match case-sensitive?
Yes. Values that differ only in capitalization or surrounding whitespace are treated as distinct rows, so normalize them first if you want them merged.

// works with your data

CSV to JSON CSV to SQL CSV to Markdown CSV to XML Sort & Dedupe Lines Slug Generator

Use this via API

Get a free API key → 
curl -X POST https://thesnaptools.com/api/v1/tools/csv-deduplicator \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"csv":"id,name 1,Ada 2,Linus 1,Ada"}'