Text Diff Checker
Compare two texts and visualize differences line by line. Green = added, red = removed. No sign-up.
Diff Checker
Compare two texts and visualize line-by-line differences
1 lines
1 lines
Paste text in both fields to see the differences
Built by
Miguel Ángel Colorado Marin
Built by
Miguel Ángel Colorado Marin
Full-Stack Developer · Guadalajara, España
I develop web apps, digital tools and full projects — from design to deployment.
How to use the text diff checker?
- 1
Paste the original text
Enter or paste the original text in the left panel. It can be any type of content: source code, documentation, articles, configurations or any text you want to use as the comparison base.
- 2
Paste the modified text
Enter or paste the modified text in the right panel. This is the new or updated version you want to compare against the original. They do not need to be the same length.
- 3
See the colored diff
The result appears automatically with each line color-coded: green for lines added in the new version, red for lines removed from the original, and grey for unchanged lines. Line numbers help you locate each exact change.
- 4
Download the .diff file
Click the download button to save the result as a .diff file in standard unified diff format. This format is compatible with git, patch and most version control and code review tools.
Frequently asked questions
What is a diff?
A diff (difference) is a representation of changes between two versions of a text. It shows exactly which lines have been added, removed or remain the same. It is the base format used by git to manage changes in source code and is widely used in code reviews and version control.
What do the green and red lines mean?
Green lines indicate content that has been added in the modified text (the right panel) and was not in the original. Red lines indicate content that existed in the original but has been removed in the modified version. Grey or uncolored lines are lines that have not changed between the two versions.
Is there a maximum text size?
The tool runs entirely in the browser without sending data to any server, so the limit depends on your device's RAM. For normal-sized texts (documents, code snippets, articles) there will be no problem. For very large files it is recommended to use command-line tools like diff or git diff.
Can I use it for code comparison?
Yes, the diff checker works perfectly with any programming language: JavaScript, Python, Java, CSS, HTML, JSON, YAML, etc. The comparison is purely textual, line by line, making it ideal for reviewing changes in code snippets, configuration files or any structured text.
Is my data private?
Yes, completely. All processing happens in your browser with pure JavaScript. No text you enter is sent to any server or stored anywhere. You can use this tool with confidential content or proprietary code without any risk.
Embed the diff checker on your site
Embed this text diff checker in any web page with a simple iframe:
<iframe
src="https://miguelacm.es/embed/diff-checker"
width="100%"
height="600"
frameborder="0"
title="Diff Checker"
></iframe>