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Text Deduplicator

Online Text and JSON Deduplicator

Text Deduplicator guide

Text Deduplicator Description

Text Deduplicator - remove duplicate lines, numeric values, and JSON array entries directly in your browser. It is built for developers, analysts, editors, and operations teams who need predictable ordering without sending data to a server. All processing runs locally in the browser, so pasted content is not uploaded to Tool3M.

Features

Supports plain multiline text, numeric values, and JSON arrays.
Provides order-preserving duplicate removal, optional sorted output, case sensitivity, line trimming, and empty-line handling.
Includes a one-click demo, clear action, copy action, live output, and visible validation errors.
Uses the shared Tool3M CodeMirror editor for comfortable multiline editing on desktop and mobile.
Keeps processing local to the browser for privacy and fast repeat work.

How to Use

1
Paste your list, numbers, or JSON array into the input editor, or click the demo button for sample data.
2
Choose the data type and adjust options such as case sensitivity, trimming, and empty-line handling.
3
Review the generated output, then click copy to use the deduplicateed result in another tool, script, spreadsheet, or document.

FAQ

Q. Is my data uploaded?
No. The transformation runs in the browser and does not upload pasted text to Tool3M.
Q. Can I use JSON objects directly?
JSON mode expects an array. Wrap object entries in an array when you need to deduplicate multiple values.
Q. Why does number mode reject some lines?
Number mode only works when every non-empty line is a finite numeric value, so mixed text is reported as an error.
Q. Does case sensitivity matter?
Yes. Disable it for human-friendly comparison, or enable it when uppercase and lowercase entries must remain distinct.

Practical Use Cases

  • Normalize API fixture lists before committing tests.
  • Clean exported spreadsheet columns before importing them into another system.
  • Prepare command-line allowlists, deny-lists, package names, or configuration keys.
  • Inspect JSON arrays from logs or browser devtools without switching to a server-side script.

Technical Background

The tool treats multiline input as a sequence separated by standard line breaks. Number mode validates each non-empty line with JavaScript numeric parsing, then compares numeric values instead of lexicographic strings. JSON mode requires the input to parse as a JSON array, because array membership is the structure the tool can transform without inventing field semantics. Complex JSON objects are compared with a stable key-deduplicateed representation, while the output preserves the original JSON values.

Limitations

  • Very large inputs are limited by browser memory and editor responsiveness.
  • JSON mode intentionally handles arrays only and does not infer object fields or nested business rules.
  • Locale-specific collation may vary slightly between browsers because comparison is delegated to the browser runtime.
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Reviewed by Tool3M Editorial Team

Updated April 25, 2026

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