Text Diff Checker

// compare two texts line-by-line with word-level highlighting — entirely in your browser

ready
Original
Changed
Lines added: 0
Lines removed: 0
Lines unchanged: 0
Paste text into both boxes above to see the differences.

About This Text Diff Checker

This free text diff checker compares two blocks of text line-by-line and highlights exactly what changed — added lines in green, removed lines in red, and the specific words that differ within a modified line. Toggle Ignore whitespace or Ignore case to skip formatting-only differences. Works entirely in your browser — nothing you paste is ever sent to a server.

Common uses: reviewing edits to a config file, comparing two versions of a code snippet, checking what changed between two drafts of an article, or spotting the difference between two JSON payloads.

Frequently Asked Questions

How does this text diff checker work?+
Paste your original text on the left and the changed version on the right. The tool compares them line by line using a longest-common-subsequence algorithm, then highlights the specific words that changed within modified lines.
What do the colors mean in the diff view?+
Green rows and highlights are lines or words added in the right-hand text. Red rows and highlights (shown with strikethrough) are lines or words removed from the left-hand text. Unhighlighted rows are unchanged.
Can I ignore whitespace or letter case when comparing?+
Yes. Turn on Ignore whitespace to treat lines that only differ by leading, trailing, or repeated spacing as identical, and Ignore case to treat "Hello" and "hello" as the same line.
Can I use this to compare code?+
Yes. Any plain text works, including source code, JSON, config files, or log output. The comparison is purely textual, so indentation and formatting differences are shown unless you enable Ignore whitespace.
Is there a limit to how much text I can compare?+
The comparison runs in your browser using a line-by-line algorithm, so very large files (thousands of lines on both sides) may be slow. For typical code snippets, config files, or paragraphs it's instant.
Does this tool send my text anywhere?+
No. Both text boxes and the diff are computed entirely in JavaScript in your browser. Nothing you paste is uploaded, logged, or stored — refresh the page and it's gone.