Compare two blocks of text, line by line or word by word.

Original Open File

Changed Open File

Result

About the Diff Checker

Compares two texts and highlights exactly what changed, in your browser. Paste or drop both versions and read the differences line by line, word by word, and character by character inside changed lines.

Every Setting

Compare

By Line treats each line as the unit, the right choice for code and configs. By Word compares running prose, so a reworded sentence shows the exact words that moved.

Ignore Whitespace

Collapses runs of spaces and tabs before comparing, so a re-indent does not count as a change.

Show Spaces and Tabs

Draws each space as a faint dot and each tab as an arrow, so a change that is only indentation or a trailing space is visible.

Ignore Case

Compares without case, so Fox and fox match.

Collapse Unchanged

Folds long identical stretches down to a few lines of context around each change, the way patch files do. Turn it off to read both texts in full.

View

Unified interleaves removals and additions in one column, the patch-file style. Side by Side puts the two versions in parallel columns.

Swap Sides

Trades Original and Changed, for when you pasted them the wrong way around.

Clear

Empties that box.

Open File

Loads a file into either side, up to 2 MB. Dropping a file straight onto a box does the same.

Pane Divider

Drag the bar between the boxes to deal the width; it remembers your split, and double-clicking resets it.

Box Height

Drag a box’s bottom-right grip to make it taller; the other box follows so the pair stays even.

Previous / Next

Steps through the changes one by one, so a long document’s three edits do not hide in the scroll.

Export

Download Patch writes a standard .patch file; Copy as Markdown formats the diff for a code-review comment or ticket. Both work in line mode.

Common Questions

What do the red and green mean?

Red is what the first text had and the second dropped; green is what the second added.

Where does the share link come from?

Small comparisons are packed into the page URL as you type, so copying the address bar shares the diff. Anything over a few thousand characters stays out of the URL.