Text Diff Checker
Compare two texts online and highlight differences. Side-by-side or inline diff view with word-level change detection. Find added, deleted, and modified content instantly. 100% browser-based, privacy first. Free, no sign-up required.
Frequently Asked Questions
What is a text diff checker?
A text diff checker compares two versions of text and highlights the differences โ what was added, deleted, or changed. It's commonly used for reviewing edits to documents, comparing configuration files, or tracking changes between drafts.
What is the difference between inline and side-by-side view?
Inline view shows both versions merged into a single text block, with deletions shown in red strikethrough and additions in green. Side-by-side view shows the original on the left and the modified on the right, with changes aligned for easy visual comparison. Use inline for quick scanning, side-by-side for detailed review.
Word-level vs character-level diff โ which should I use?
Word-level diff treats each word as a unit of comparison โ best for natural language text like articles, emails, or code comments. Character-level diff compares character by character โ useful for short strings, URLs, or finding subtle spelling changes within a word.
How does the diff algorithm work?
The tool uses the Longest Common Subsequence (LCS) algorithm to find the longest sequence of matching lines or words between the two texts. Everything not in the LCS is marked as added or deleted. The algorithm runs entirely in your browser โ no data is sent to any server.
What do "Ignore whitespace" and "Ignore case" do?
Ignore whitespace trims leading/trailing spaces from each line and collapses multiple spaces into one before comparing โ useful when formatting changes shouldn't count as diffs. Ignore case converts both texts to lowercase before comparison, so "Hello" and "hello" are treated as identical.
How is this different from the Document Compare tool?
The Document Compare tool compares two Word (.docx) files at the paragraph level. This Text Diff Checker compares raw text โ no file format, just paste and compare. It's ideal for comparing code snippets, configuration files, plain text drafts, or any text without formatting.
Is my data safe?
Yes, all comparison happens entirely in your browser using JavaScript. Your text is never uploaded to any server. This tool works offline once the page is loaded.
What's the maximum text size?
There's no hard limit โ it depends on your browser's memory. The tool handles tens of thousands of words without issues. For very large texts (hundreds of thousands of words), the comparison may take a few seconds but should still work.
Is this tool free?
Yes, completely free with no sign-up required. All text comparison and diff highlighting happens in your browser using JavaScript. No watermarks, no limits, no hidden costs.