Paste the original text
Copy your original version into the first text area of the online text diff checker. This is the baseline version you want to compare against, clearly labeled as original for easy reference.
Text Diff Checker
Paste two versions of text and see the differences highlighted instantly. Compare line by line with additions shown in green, deletions in red, and unchanged text in gray. Perfect for reviewing document changes, code diffs, and content edits.
Workspace
Use the tool below. Your inputs stay local when the tool supports browser-only processing.
Last reviewed: · Testing methodology
Workflow
How to use the Text Diff Checker
Paste the modified text
Copy your edited or newer version into the second text area. The online text diff checker highlights differences between the two texts with color coding as soon as both versions are entered.
Review the differences
Additions appear in green and deletions in red so you can review changes at a glance. This online text diff checker helps you verify edits in collaborative documents, track revisions, and ensure no content was lost during editing.
How this tool works
The component compares the two entered sequences and renders their differences without uploading either version.
- Engine: Client-side sequence comparison
- Supported input: two plain-text versions
- Output: added, removed, and unchanged segments
- Input
- Old: color New: colour
- Output
- Removed 'color' and added 'colour'
Limits, edge cases, and troubleshooting
Use it for configs, copy edits, and small code snippets. Normalize line endings if every line appears changed.
- Very large inputs can consume significant time and memory.
- It compares text, not document formatting, comments, binary files, or semantic equivalence.
When to use another workflow
Use Git or a desktop diff application for repositories, directory comparison, syntax-aware views, history, and merge conflict resolution.
| Option | Best for | Trade-off |
|---|---|---|
| This browser tool | Quick, private, one-off work | Limited by browser memory and the documented feature set |
| Desktop or command-line tool | Batch jobs and repeatable automation | Requires installation and setup |
Verification
Reviewed by the Free Online Tools Nest Team on 2026-08-26. The interface, output path, and documented limitations were checked against the current implementation. See our testing methodology for the review process.
Read the testing methodologyText Diff Checker — Frequently Asked Questions
How do I use an online text diff checker to compare two documents?
Paste the original text in the left panel and the modified text in the right panel of the online text diff checker. The tool instantly highlights added words in green and removed words in red, making every change visible for quick review.
Can the online text diff checker compare code files or just regular text?
The online text diff checker works with any text-based content including prose, code, configuration files, and data entries. It performs character-level and line-level comparison that catches even small changes like a single semicolon or a corrected typo.