Duplicate Detector
Upload a CSV, or try the sample: find exact duplicates and near-duplicates.
Your file is processed entirely in your browser. It is never uploaded anywhere.
What is happening?
An exact duplicate matches on every column. A near-duplicate matches on every column except one: often a sign of a typo, a re-entry with a corrected field, or an update that should have overwritten the original row instead of adding a new one. Both are common, quiet sources of inflated counts and skewed averages.
Under the Hood
CSV parsed in-browser (hand-rolled parser)
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Exact match: identical key across every column
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Near match: identical except exactly one column
Inputs
- Any CSV with a header row
Processing
- Row-key matching
- Single-column-diff matching
Output
- Exact duplicate pairs
- Near-duplicate pairs with the differing column
Technology
- Vanilla JavaScript, FileReader API
- No server: nothing leaves your browser
Explore another experiment
More Playground experiments are on the way.