↔ Text Diff Checker
Paste two versions of any text and instantly see what changed. Supports line-by-line and word-level comparison with color highlighting. Your text never leaves your browser.
Free Online Diff Checker — Compare Text, Code, and Documents
A diff tool compares two texts and highlights what was added, removed, or left unchanged. It's invaluable for reviewing code changes before committing, comparing document revisions, spotting accidental changes, and validating that a refactoring preserved behavior.
How Diff Algorithms Work
Most diff tools use the longest common subsequence (LCS) algorithm to find the longest sequence of lines (or words/chars) that appear in both versions, then mark everything else as an insertion or deletion. The classic Unix diff command and Git's diff engine both use LCS-based approaches.
Compare JSON, Code, or Config Files
This tool works on any text — JSON, YAML, CSS, JavaScript, Python, SQL, or prose. For comparing configuration files between environments, paste both versions and select "Line-by-line" mode to see exactly what changed. Use "Word-level" mode for comparing sentences or paragraphs.