Diff Checker
Paste two versions of a text and see exactly what was added, removed and changed, line by line or word by word.
About Diff Checker
Paste an original on the left and a revision on the right, and every addition, deletion and change is highlighted. It uses the same class of algorithm as version control diffs, so it aligns matching sections properly instead of giving up as soon as one line differs.
Two granularities are available. Line mode is best for code, configuration and structured data, where the unit of change is a line. Word mode is better for prose, because a single edited word in a paragraph shows as that word changed rather than the whole line rewritten.
Options for ignoring case and collapsing whitespace are included, which cut through the noise when comparing files that went through different editors or formatters. A summary counts added, removed and unchanged lines so you can gauge the scale of a change before reading it.
How to use it
- 1Paste the original text into the left pane.
- 2Paste the changed version into the right pane.
- 3Choose line or word comparison depending on the content.
- 4Read the highlighted result — green is added, red is removed.
Common uses
- Checking what changed between two versions of a contract or policy
- Reviewing edits before accepting them into a document
- Spotting the difference between two configuration files
- Verifying that a copy-paste did not silently alter content
Frequently asked questions
What is the difference between line and word mode?
Line mode treats each line as one unit, so any change marks the whole line. Word mode compares individual words, so an edited word inside a long paragraph shows precisely. Use line mode for code and word mode for prose.
Can it compare files rather than pasted text?
Paste is the primary input, and it handles large blocks comfortably. For file comparison, open both files and copy their contents in — the comparison itself is identical either way.
Is my text sent anywhere?
No. The comparison runs entirely in your browser, which makes this usable for contracts, credentials and anything else you should not paste into a remote service.
Why do two visually identical texts show as different?
Usually invisible characters — trailing spaces, tabs against spaces, or Windows line endings against Unix ones. Enable the whitespace option to collapse those and see whether a real difference remains.