How is the difference calculated?

Texts are compared with a Myers diff, line by line, then changed lines are compared word by word so you see exactly what moved inside a line.

Can it compare code or JSON?

Yes, it works with any plain text, including code, JSON, or configuration files.

Is my text uploaded anywhere?

No, the comparison runs entirely in your browser — nothing is sent to a server.

Can I switch between line-level and word-level diffing?

The editor always highlights changed words within a changed line. Use Side by side or Inline to change the layout.

Does it ignore whitespace differences?

Yes — tick Ignore whitespace (and Ignore case) and those changes are no longer counted or shown.

Can I see the diff as a unified patch?

Yes. Copy patch or Patch downloads a standard unified diff with three lines of context, ready for git apply or patch.

Does it handle very large text blocks?

Yes. It uses an efficient diff algorithm rather than a full comparison table, so tens of thousands of lines are fine, though the editor itself may be slower with very large files.

Can I edit the text after comparing?

Yes. Both sides stay editable and the comparison updates as you type. Swap exchanges the two sides.

Processed 100% locally in your browser

Text Diff Checker

Compare two texts side by side or inline with word-level highlights and patch export — 100% local.

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Quick Answer

Text Diff Checker lets you: Compare two texts side by side or inline with word-level highlights and patch export — 100% local. To start, type or paste on either side, or use Open original and Open changed.

How to use this tool

1
Paste or open both texts
Type or paste on either side, or use Open original and Open changed.
2
Choose how to compare
Switch between side-by-side and inline, and tick ignore whitespace or ignore case.
3
Review the changes
Added and removed lines are coloured, changed words are highlighted inside each line, and the status bar counts them.
4
Export
Copy or download the differences as a standard unified patch.

Frequently Asked Questions

JSON Formatter

A full-screen JSON editor: format, validate, repair, sort keys, and explore as a tree, table or JSONPath query — 100% local.

Case Converter

Convert text between 14 case styles live — Unicode-aware, per line, and ideal for identifiers.

Text Diff Checker

How to use this tool

Paste or open both texts

Choose how to compare

Review the changes

Export

Frequently Asked Questions

How is the difference calculated?

Can it compare code or JSON?

Is my text uploaded anywhere?

Can I switch between line-level and word-level diffing?

Does it ignore whitespace differences?

Can I see the diff as a unified patch?

Does it handle very large text blocks?

Can I edit the text after comparing?

Related Tools

JSON Formatter

Case Converter

Text Diff Checker

How to use this tool

Paste or open both texts

Choose how to compare

Review the changes

Export

Frequently Asked Questions

How is the difference calculated?

Can it compare code or JSON?

Is my text uploaded anywhere?

Can I switch between line-level and word-level diffing?

Does it ignore whitespace differences?

Can I see the diff as a unified patch?

Does it handle very large text blocks?

Can I edit the text after comparing?

Related Tools

JSON Formatter

Case Converter