Find Fuzzy Duplicates in JSON Files Online
Find near-duplicate rows in JSON files using Levenshtein edit distance or Jaro-Winkler similarity — all in your browser. Set your own threshold and download the matched pairs as CSV — no upload required.
About this tool
Find and remove near-duplicate rows in a JSON file using string similarity matching — catching typos, abbreviations, and inconsistent formatting that exact deduplication misses. Set a similarity threshold, choose the column to match on, and download a deduplicated file with flagged pairs. Ideal for cleaning customer names, addresses, and product descriptions. All processing runs locally in your browser.
Frequently Asked Questions
How is fuzzy deduplication different from exact deduplication for JSON files?
Exact deduplication removes rows where all columns match perfectly. Fuzzy deduplication finds rows that are similar but not identical — for example "John Smith" and "Jon Smith" or "123 Main St" and "123 Main Street". It uses string similarity to identify near-matches that represent the same real-world entity.
What similarity threshold should I use when fuzzy-deduplicating a JSON file?
Start with 0.85 (85% similarity). A lower threshold catches more duplicates but risks merging distinct records. A higher threshold is more conservative and safer when small differences are meaningful. Review the flagged pairs at your chosen threshold before committing.
Can I fuzzy-deduplicate on multiple columns in a JSON file?
Choose the single column that best identifies the entity — typically a name, address, or description. For multi-column matching such as first name + last name together, use the Concatenate Columns tool to combine them into one column before running fuzzy deduplication.
Is my data private?
Yes — completely. Your file is never uploaded to any server. Everything runs locally in your browser using WebAssembly — processing happens entirely inside your tab. Once you close the tab, nothing is retained.
What is the maximum file size?
The free limit is 50 MB. For larger files, performance depends on your device's available memory — most modern machines handle 500 MB to 1 GB comfortably.
Related Tools
Convert Case in JSON Files Online
Convert text columns to UPPERCASE, lowercase, or Title Case in JSON files directly in your browser. Apply case conversion to any or all text columns at once — no upload required.
Aggregate JSON Files Online
Group and aggregate JSON files by any column directly in your browser. Calculate sum, average, min, max, and count for any numeric column — no upload required.
Round Numbers in JSON Files Online
Round numeric columns in JSON files to any number of decimal places directly in your browser. Set precision per column with a simple slider — no upload required.
Add Conditional Column to JSON Files Online
Add a new column to JSON files based on an if/else condition directly in your browser. Set a value for rows that match and a different value for rows that don't — no upload required.
Extract with Regex from JSON Files Online
Extract text matching a regular expression from JSON files directly in your browser. Pull out emails, URLs, phone numbers, or any pattern into a new column — no upload required.