What algorithm does this use?

This tool uses the Myers diff algorithm, the same algorithm used by Git. It finds the minimal set of changes between two texts efficiently.

What is the difference between compare modes?

Character mode shows every character change, word mode groups changes by words (best for prose), and line mode shows changes per line (best for code).

Can I use this for code review?

Yes! Line mode is perfect for code review. It highlights added and removed lines similar to GitHub pull request diffs.

Yes, all comparison happens locally in your browser. No text is sent to any server.

Can I compare two Word documents or PDFs?

Yes. Click "Open file" or drop a .docx or .pdf on either side. The text is extracted in your browser and compared line by line. Formatting changes are not compared, and scanned PDFs have no text to extract, so use the visual Compare PDF tool for those.

How do I read the diff?

Lines marked with a minus (red) exist only in the original, lines marked with a plus (green) exist only in the changed text, and paired lines show the exact words that changed in a darker shade. Unchanged stretches are collapsed; click them to expand.

How do I ignore whitespace or indentation changes?

Tick "Ignore whitespace" to treat lines as equal when they differ only in spaces or tabs, or "Ignore trailing spaces" to ignore only spaces at line ends. "Ignore case" treats upper and lower case as the same.

Why does every line show as changed?

This usually means the line endings differ (Windows CRLF vs Unix LF). The tool normalises line endings automatically and tells you when they differed, so this should not happen here.

Can I compare JSON files with keys in a different order?

Yes. Turn on "Format JSON (sort keys)" and both sides are pretty-printed with keys sorted before comparing, so only real value changes are shown.

Can I get the result as a patch file?

Yes. "Copy diff" copies a standard unified diff and ".diff" downloads it. It is the same format git diff produces, so it can be read by code review tools or applied with patch -p0.

What algorithm does this use?

This tool uses the Myers diff algorithm, the same algorithm used by Git. It finds the minimal set of changes between two texts efficiently.

What is the difference between compare modes?

Character mode shows every character change, word mode groups changes by words (best for prose), and line mode shows changes per line (best for code).

Can I use this for code review?

Yes! Line mode is perfect for code review. It highlights added and removed lines similar to GitHub pull request diffs.

Yes, all comparison happens locally in your browser. No text is sent to any server.

Can I compare two Word documents or PDFs?

Yes. Click "Open file" or drop a .docx or .pdf on either side. The text is extracted in your browser and compared line by line. Formatting changes are not compared, and scanned PDFs have no text to extract, so use the visual Compare PDF tool for those.

How do I read the diff?

Lines marked with a minus (red) exist only in the original, lines marked with a plus (green) exist only in the changed text, and paired lines show the exact words that changed in a darker shade. Unchanged stretches are collapsed; click them to expand.

How do I ignore whitespace or indentation changes?

Tick "Ignore whitespace" to treat lines as equal when they differ only in spaces or tabs, or "Ignore trailing spaces" to ignore only spaces at line ends. "Ignore case" treats upper and lower case as the same.

Why does every line show as changed?

This usually means the line endings differ (Windows CRLF vs Unix LF). The tool normalises line endings automatically and tells you when they differed, so this should not happen here.

Can I compare JSON files with keys in a different order?

Yes. Turn on "Format JSON (sort keys)" and both sides are pretty-printed with keys sorted before comparing, so only real value changes are shown.

Can I get the result as a patch file?

Yes. "Copy diff" copies a standard unified diff and ".diff" downloads it. It is the same format git diff produces, so it can be read by code review tools or applied with patch -p0.

Diff Checker

Compare two texts and see the differences highlighted line by line.

Original text

0 lines · 0 characters

Changed text

0 lines · 0 characters

Runs entirely in your browser using the Myers diff algorithm (the same approach Git uses). Your text and files are never uploaded.

What can you compare?

Two versions of code, config or plain text

Paste or drop the files. Changed lines are paired and the exact words or characters that changed are highlighted.

Two Word documents (.docx)

The text is read in your browser and compared. Formatting changes such as bold or font size are not compared.

Two PDFs with selectable text

The text of every page is extracted and compared line by line.

Scanned PDFs, or how the pages look

Scanned pages have no text to read. Compare the page images visually instead, or run OCR first.

Compare PDF pages visually

JSON where only key order or formatting changed

Turn on "Format JSON (sort keys)" so reordered keys and spacing do not show up as changes.

Features

Side-by-side comparison
Line-by-line diff view
Added/removed highlighting
Line number display
Swap texts easily
Statistics summary
100% client-side
No signup required
Word and character level highlighting
Ignore whitespace, trailing spaces or case
Compare Word (.docx) and PDF files
JSON compare with sorted keys
Jump between changes
Copy or download a unified .diff

Perfect For

Code Review

Compare code versions to identify changes and modifications.

Document Editing

Track changes between different versions of documents.

Configuration

Compare config files to spot differences between environments.

Contracts & Drafts

Open two versions of a Word or PDF document and see exactly which words changed.

Frequently Asked Questions

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Diff Checker

What can you compare?

Two versions of code, config or plain text

Two Word documents (.docx)

Two PDFs with selectable text

Scanned PDFs, or how the pages look

JSON where only key order or formatting changed

Features

Perfect For

Code Review

Document Editing

Configuration

Contracts & Drafts

Frequently Asked Questions

Related Developer Tools

Was this tool helpful?

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WhatsApp Bot Builder

AI Website Chatbot

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Diff Checker

What can you compare?

Two versions of code, config or plain text

Two Word documents (.docx)

Two PDFs with selectable text

Scanned PDFs, or how the pages look

JSON where only key order or formatting changed

Features

Perfect For

Code Review

Document Editing

Configuration

Contracts & Drafts

Frequently Asked Questions

What algorithm does this use?

What is the difference between compare modes?

Can I use this for code review?

Is my data secure?

Can I compare two Word documents or PDFs?

How do I read the diff?

How do I ignore whitespace or indentation changes?

Why does every line show as changed?

Can I compare JSON files with keys in a different order?

Can I get the result as a patch file?

Related Developer Tools

Was this tool helpful?

Put your customer conversations on autopilot

AI Voice Assistant

WhatsApp Bot Builder

AI Website Chatbot

Video Localization

Call Analytics

Edesy CRM

Number Masking

Virtual Phone Number

SIP Trunking

Shopify Subscriptions