Processing boundary
Input is processed only in the active browser tab's memory and is not sent to a ByteQuant server.
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Data & developer
CSV Deduplicator & Duplicate Finder
Detects comma, semicolon, or tab delimiters, parses quoted fields, and keeps the first or last row by a selected column list. Case and surrounding-whitespace normalization are explicit options.
✓ Free✓ No account✓ In-browser
Persistent storage
Input and output are not stored. The optional usage counter keeps only tool identity and count, never content.
Verification
Output comes from disclosed rules or browser APIs and needs independent review before high-impact use.
A result in three steps
- 01
Paste CSV with a header and enter key columns.
- 02
Choose matching rules and which row to retain.
- 03
Review duplicate counts and download the cleaned CSV.
When is this tool useful?
- ✓ Cleaning email lists
- ✓ Deduplicating exported records
- ✓ Data-quality checks before merging
Important limitation
Automated output is a preliminary assessment. Do not use it alone for legal, financial, medical, or security-critical decisions.
LEARN THE WORKFLOW
Guides for this tool
Safely Converting YAML, XML, JSON, and CSV in the Browser
A parsing, flattening, deduplication, and schema-validation workflow that avoids silent data loss.
Read guide →ABOUT THIS TOOL
Frequently asked questions
Does this tool send input to a server?+
No. Processing runs in this browser tab. Data leaves the page only when you choose to copy or download the result.
Is the result definitive?+
The tool produces consistent output from disclosed rules and browser APIs, but context, data quality, and method limitations can affect it. Verify high-impact decisions.
Is input saved?+
No. Tool input is not persisted. With consent, only tool identity and usage count may be kept on this device for personal shortcuts.