How to Use
- Paste your original text in the left pane.
- Paste the modified text in the right pane.
- Click 🔍 Compare Text in the top toolbar to generate the diff below.
- Cyan lines (+ sign) show additions, red lines (- sign) show deletions.
- Use the ⇆ Swap Inputs button to quickly reverse the original and modified texts.
What Is a Text Diff?
Frequently Asked Questions
What is a text diff?
A diff (short for 'difference') compares two pieces of text line by line and shows what changed: additions (lines only in the modified text), deletions (lines only in the original), and unchanged lines. This tool uses a longest-common-subsequence (LCS) algorithm to produce an accurate comparison instantly in your browser.
Can I compare code files?
Yes. Paste any plain text into either pane — source code, configuration files, JSON, Markdown, or prose. The tool does a line-by-line diff, so it works best when content is structured by newlines.
Does this tool send my text to a server?
No. The comparison runs entirely in your browser. Your text is never uploaded or stored anywhere.
What do the colors mean?
Teal lines (marked with +) are additions that appear in the modified text but not the original. Red lines (marked with -) are deletions present in the original but removed in the modified version. Amber lines (marked with ~) are changed lines, where the word-level highlight shows exactly which words differ. Unchanged lines are dimmed.
Can it show which words changed within a line?
Yes. When a line is edited rather than fully added or removed, the tool runs a second word-level comparison on that line and highlights only the specific words that differ — added words on the modified side, deleted words on the original side. This makes it easy to spot a single changed word in an otherwise identical sentence.
What is the difference between Split and Unified view?
Split view shows the original and modified text in two columns side by side, which is best for reading the two versions together. Unified view stacks the changes in a single column with - and + markers, the same format Git and code review tools use. Switch between them anytime with the Split / Unified tabs; the comparison updates instantly.
Can I ignore case or whitespace differences?
Yes. Toggle 'Ignore case' to treat uppercase and lowercase as equal, and 'Ignore whitespace' to ignore differences in spacing and indentation. The original text is still displayed exactly as you pasted it — only the matching is relaxed.
Is there a size limit for the text I can compare?
There is no hard limit imposed by the tool. Very large texts (hundreds of thousands of lines) may make the browser slow while computing the diff, but smaller documents compare instantly.