Paste both texts or load the sample, then run Compare.
Diff Checker v1.0.21
The Diff Checker Tool is a lightweight, web-based utility designed to compare two blocks of text and highlight their differences. It provides an intuitive interface for users to paste texts, compare them, and view the changes in a clear, colour-coded format. The tool compares multiline texts, programming code, HTML, or other textual content. All processing is done client-side, right in the browser.
A diff checker is an online tool that compares two blocks of text or code to highlight their differences. It shows added content in green, removed content in red, and unchanged content in neutral formatting. Developers use diff checkers to compare code versions, track changes in configuration files, and identify modifications between file versions. For JSON documents, format both sides with the JSON Formatter first so the diff stays readable; use the Text Analyzer to compare word counts on either side, or the JavaScript Minifier when you are diffing bundled scripts.
When you need to compare code online, the workflow is straightforward: put the earlier or reference version on the left and the updated version on the right, then run Compare. The tool works as a code difference checker for patches, pull requests, config tweaks, and any pair of text files you want to line up.
Results use familiar diff styling—additions, removals, and edits are easy to scan—and you can step through each change with Prev and Next. For plain prose or mixed content, the same compare flow applies; only the highlighting mode changes when the input looks like code.
Supported languages for automatic syntax highlighting include JavaScript, JSON, HTML, and CSS (detection runs on your pasted or uploaded text). For JSON, format both sides first if minified output makes the diff hard to read. You can still diff Python, Java, C++, XML, and other plain-text code; those comparisons stay accurate even when highlighting stays minimal.
Files you drop into the editors are read on your device only. As with the rest of this tool, your input is processed in this browser and is not uploaded by the diff checker.
Use this page as a file diff checker when you already have two versions on disk. Click Upload File in the left or right pane, or drag a file onto either editor. Each drop or pick loads one file at a time into that pane; load the other version in the opposite pane, then click Compare.
The picker accepts common text and code types (for example plain text, JSON, JavaScript, XML, YAML, and CSV). Files larger than 5 MB are rejected to keep comparisons responsive in the browser. Content is decoded and shown in the editor on your device only—it is never sent to our servers.
After a comparison finishes, Download .patch saves the current diff as a unified patch file named comparison.patch. The patch header uses the filenames from uploaded files when available, or original and modified when you pasted the text instead.
The export is the same unified diff format Git and other tools expect: hunks with --- / +++ headers and + / - lines for additions and removals. Your Ignore Whitespace toggle is applied when the patch is built, so the file matches what you see in the results panel.
You can open the patch in an editor for review, share it in a ticket, or apply it with git apply when the paths in the header match files in your local repository.
.patchfile, using loaded filenames or original and modified labels; Ignore Whitespace follows the native patch semantics of the diff library.Paste the first text block into the left textarea and the second text block into the right textarea, or click Upload File in either pane.
Keep it checked to ignore differences in spaces, tabs, and line endings, or uncheck it to compare whitespace exactly. Browser textareas normalize typed and pasted line endings to LF; use file drops or shared links to compare raw line endings, which appear as ␍.
Click the Compare button to analyze the differences between the two texts.
The differences appear below in a styled output area with added lines in green, removed lines in red, and unchanged lines unstyled.
Example Input 1:
function greet(name) {
console.log("Hello, " + name);
}Example Input 2:
function greet(name) {
console.log("Hi, " + name);
}Example diff checker result output:
While the tool efficiently handles moderate-sized texts, extremely large inputs may impact performance because it is not optimized for very large datasets.
This checker compares two texts or files and highlights added, removed, and changed lines in the browser. These tutorials cover Git merge versus rebase and a Git command reference for reviewing committed changes.
Paste or upload the original file into the left editor and the revised file into the right editor, then click Compare. The diff checker highlights added, removed, and changed lines so you can review code differences in your browser. Your input is processed locally and is not uploaded by the tool.
There is no practical difference: both names describe the same kind of tool that compares two texts or files and shows what changed. "Diff checker" is common in developer tools; "difference checker" is the same idea in plain language. This page is a diff checker you can use to compare code or any text side by side.
Yes. This diff checker runs in your browser, so you can compare code snippets, configs, or documents online without a desktop app. Open the page, add your two versions, and run Compare whenever you need a quick code diff or text comparison.
Yes! Once the page loads, all comparisons happen locally in your browser, so you can use it without an internet connection.
It handles multiline text and code well, including syntax highlighting, but performance may slow with extremely large inputs because everything processes in-browser. For huge files, consider splitting them or using a desktop diff tool.
This is intentional for cleaner code comparisons because minor formatting changes do not clutter the results. You can toggle the Ignore Whitespace option off if you need exact matching, including every space and newline. Carriage returns from dropped files or shared links are shown as ␍ in that mode so line-ending differences stay visible without adding blank rows.
Yes. You can compare text from any source regardless of language. The tool performs a text-based diff, so it works across programming languages and file types.
No. All comparisons are processed in your browser. Your code is never sent to our servers, which keeps the comparison private.
The diff checker supports plain text, code files such as Python, JavaScript, Java, and C++, plus JSON, XML, HTML, and CSS. You can paste any textual content into the two editors.
Yes. The diff checker is completely free and does not require registration. You can compare unlimited text and code differences instantly.
Yes. Click Upload File or drag a local text file into the left or right pane—each pane accepts one file at a time. The file is read on your device only (not uploaded to a server) and appears in that editor so you can compare it against pasted text or a second uploaded file.
After you run Compare, use Download .patch to save a unified diff of the current left and right inputs as comparison.patch. The export uses the loaded filenames when you uploaded files, or the labels original and modified otherwise. It follows your Ignore Whitespace setting, matching the on-screen diff.
The .patch file is a standard unified diff you can review in any text editor or apply with Git: save both versions, then run git apply comparison.patch from a repository that contains the original file paths named in the patch header. Always inspect the patch before applying it to production code.
Please message us for any bug reports, feature requests, or feedback.