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Text Diff

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About this tool

Spotting the one changed line between two 500-line files by eye is a losing game. This comparer puts two texts side by side and highlights exactly what changed between them, down to individual characters within a line, using the same diff engine that powers VS Code.

The use cases go well beyond code. Compare two versions of a config file to see which setting a deployment actually changed, review a contract revision against the copy you approved, or verify that a find-and-replace touched only the lines it should. A toggle switches between side-by-side and inline layouts to suit the size of the change.

How to use

  1. Paste the original text into the left pane, or click its Load File button to open a file.
  2. Paste the revised text into the right pane, or load its file the same way.
  3. Read the comparison: changed lines are marked, and within each line the specific characters that differ are highlighted.
  4. Use the toggle to switch between side-by-side and inline layouts, whichever reads better.
  5. Edit either pane directly to test further changes; the highlights update as you type.

The documents you compare here can be the sensitive kind: contracts, configuration containing hostnames, unreleased code. Both panes exist only in your browser's memory, the diff is computed locally by the same algorithm VS Code runs on your desktop, and no fragment of either text is uploaded or retained after you close the tab.

Frequently asked questions

What do the different highlights mean?

Lines that were added or removed are tinted across their full width, while stronger highlighting inside a line marks the exact characters that changed. A one-word edit in a long paragraph shows up as a small bright region instead of forcing you to re-read the whole line.

When should I use inline view instead of side-by-side?

Side-by-side is best when the two versions have diverged a lot, because you can scan each version independently. Inline view stacks old and new lines in a single column, which is easier to read for small scattered edits and more comfortable on narrow screens.

Can I compare two files without pasting their contents?

Yes. Each pane has its own Load File button, so you can open the old file on the left and the new file on the right directly from your device. Your browser reads the files locally and their text appears in the panes ready to compare.