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Diff Checker

New Runs in browser

Compare two texts, code files, or documents side by side — word-level diff highlighting, private and browser-based.

Last updated 31 Mar 2026

Compare two blocks of text, source code, or plain-text files with split (side-by-side) or unified (patch-style) diff views. Word-level highlighting shows exactly which words changed within modified lines. Ignore whitespace, case, or blank lines to focus on meaningful differences. All comparisons run privately in your browser.

Left file

Load any supported plain-text or code file.

Click to upload or drag and drop

TXT, MD, JSON, YAML, YML, XML, CSV, JS, JSX, TS, TSX, HTML, CSS, DIFF, PATCH up to 2MB

 

 

Right file

Compare a second file side by side.

Click to upload or drag and drop

TXT, MD, JSON, YAML, YML, XML, CSV, JS, JSX, TS, TSX, HTML, CSS, DIFF, PATCH up to 2MB

 

 

 

Left input

0 lines · 0 chars

Right input

0 lines · 0 chars

0

Added

0

Removed

0

Changed

0

Unchanged

100%

Similarity

No differences

Status

Split comparison

0 rows

Paste text or load files to compare

Diff Checker runs entirely in your browser and keeps both inputs local.

Compare pasted text, config files, Markdown, CSV, JSON, and source code without uploading anything. Split view is best for inspection, while unified view is ready to copy or download as a patch.
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How to use

  1. 1

    Paste or load your original text

    Paste the original (before) version into the left panel, or click the file button to load a plain-text file from your device.

  2. 2

    Paste or load the modified text

    Paste the modified (after) version into the right panel, or load a second file.

  3. 3

    Set comparison options

    Toggle Ignore Whitespace, Ignore Case, or Ignore Blank Lines to reduce noise and focus on meaningful differences.

  4. 4

    Switch between split and unified views

    Use Split view for side-by-side inspection where added lines show in green and removed in red. Switch to Unified view for a patch-style stream of changes.

  5. 5

    Export the diff

    Click Download to save the unified diff as a .diff file for sharing, code reviews, or attaching to a bug report.

Frequently asked questions

Does Diff Checker upload my text or files?
No. All comparisons run entirely in your browser. Text is processed locally and never sent to a server, making this safe for private notes, credentials, and proprietary source code.
What file types can I compare?
You can compare any plain-text format: .txt, .md, .json, .yaml, .yml, .xml, .csv, .js, .ts, .tsx, .jsx, .html, .css, .py, .go, .diff, .patch, and more. Binary files are not supported.
What is the difference between split and unified view?
Split view shows both versions side by side in two columns — useful for visually scanning changes. Unified view combines changes into a single column with + lines for additions and - lines for removals, matching the format of git diff output.
What does word-level diff do?
Word-level highlighting identifies the exact words that changed within a modified line, rather than just marking the entire line as changed. This is especially useful for spotting a single renamed variable or corrected word inside a dense block of text.
Can I ignore formatting-only differences?
Yes. Toggle Ignore Whitespace to skip indentation and spacing differences, Ignore Case for case-insensitive comparison, and Ignore Blank Lines to skip empty line additions or removals.
Can I use this to compare git commits?
Yes. Run git show <commit> or git diff <base>..<head> in your terminal, copy the output, and paste it here to view it with syntax highlighting. For the native comparison, paste both file versions directly.
Is there a character or file size limit?
The tool handles files up to 2 MB per side. Very large files may take a moment to diff but all processing remains in your browser.
Can I download the diff result?
Yes. The Download button exports the unified diff as a .diff file in standard patch format, compatible with git apply, patch, and most code review tools.
Does this work for comparing JSON files?
Yes, as a plain-text line diff. For a semantic JSON comparison that ignores key ordering, format your JSON first using the JSON Formatter tool, then paste both versions here for a cleaner diff.

Diff Checker gives you a fast, private way to compare two versions of any text —

source code, Markdown, JSON, YAML, XML, CSV, config files, or prose. Paste content

into the two panels or load plain-text files from your device, then switch between

split view (side-by-side columns) or unified view (patch-style with + and - lines)

depending on whether you prefer visual scanning or reviewing changes sequentially.

Word-level diff highlighting goes beyond line-level comparison: within any changed

line, the exact words that differ are highlighted, making it easy to spot a single

renamed variable or corrected typo inside a dense paragraph.

Noise-reduction options let you ignore whitespace differences, case changes, and

blank lines so you can focus on the actual content changes. Export the result as a

unified .diff patch file for use in code reviews, bug reports, or version control

workflows.

Every comparison runs entirely in your browser — no files are uploaded and no text

is sent to a server. Your private notes, credentials files, and proprietary code

stay on your device.

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