Text Diff Checker - Compare Text Differences Online Free

How to Use the Text Diff Checker

1. Paste original text in the left textarea — this is your reference or “before” version
2. Paste changed text in the right textarea — this is your updated or “after” version
3. See differences highlighted — added text appears in green, removed text in red, and unchanged text remains neutral
4. Review character-level diff — inline highlights show exactly which characters changed within a line, not just entire lines
5. Copy or reset — copy the comparison or clear both fields to start a new diff

All processing happens in your browser. Nothing is uploaded to any server.

Features

• Side-by-side comparison — see both versions displayed simultaneously for easy visual comparison
• Color-coded diff — green for additions, red for removals, neutral for unchanged content
• Inline diff — character-level difference detection shows exactly what changed within each line
• Line numbers — both panels show matching line numbers so you can track which lines were modified
• 100% private — everything runs in your browser — your text never leaves your computer
• Instant results — diff appears as you type or paste with no delay

Use Cases

• Code review — compare two versions of source code to see what changed before committing
• Writing edits — track editorial changes between drafts of articles, blog posts, or documents
• Configuration comparison — compare config files across servers or environments to find discrepancies
• Plagiarism checking — quickly spot similarities and differences between two text samples
• Data verification — compare exported data, CSV files, or JSON outputs to identify unexpected changes

FAQ

What makes inline diff different from line-level diff?

Line-level diff only shows which lines are different. Inline diff goes further and highlights exactly which characters within those lines changed. This is especially useful in code review where a single variable name change on a long line might be hard to spot otherwise.

Is there a character limit?

The diff checker handles texts up to several thousand lines. For extremely large documents (10,000+ words), performance may slow down. For very large comparisons, consider comparing sections separately.

Can I compare files instead of pasting text?

Currently the tool works by pasting text directly. You can open files in a text editor, copy the content, and paste it into the appropriate textarea.

How accurate is the diff algorithm?

The tool uses a modified Myers diff algorithm, the same algorithm used by Git for comparing text. It produces minimal, accurate diffs that show the smallest possible set of changes between two texts.

Does it compare whitespace?

Yes. Whitespace differences (extra spaces, tabs, trailing newlines) are included in the diff. If you’re comparing code where whitespace doesn’t matter, keep this in mind — trailing spaces will appear as changes.

Tips

• For code diffs, paste the current version on the left and your changes on the right — it mirrors the Git diff convention
• Use inline diff to spot subtle character-level changes like swapped letters in variable names
• The tool works great for comparing JSON configurations, SQL queries, or any structured text
• If the diff looks too noisy, check for inconsistent whitespace (tabs vs spaces) between the two versions