Text Diff

A text diff tool answers a question that comes up constantly when working with documents, configuration, or copy: what exactly changed between two versions? Rather than reading both blocks side by side and hunting for differences by eye, this tool compares them word by word and highlights exactly what was added and what was removed, so the change is obvious at a glance.

Paste (or type) the original text on the left and the changed text on the right, and the difference is computed live as you edit either side — no button to click, no delay. Removed words are struck through and shaded, added words are shaded in a different color, and everything that stayed the same is shown as plain text, so the unchanged bulk of a document doesn't distract from what actually moved.

The comparison works at the word level rather than the character or line level, which tends to match how people actually read changes: a single word swapped inside a sentence shows up as a clean delete-and-insert pair instead of a scramble of individual character edits. This makes it well suited to prose, commit messages, configuration values, or any text where the meaningful unit of change is a word or phrase rather than a single character.

Like every tool in this toolbox, the comparison happens entirely in your browser — nothing you paste is uploaded, logged, or sent to a server. That matters when you're comparing something you'd rather not send to a third-party website, such as an internal document, a contract redline, or a draft containing personal information. The tool keeps working with no internet connection once the page has loaded.

In practice this gets used for reviewing edits to an article or email before sending, comparing two versions of a configuration file or environment variable list, checking what changed in a piece of copy after a rewrite, or spotting an accidental change buried in a long block of text. Use the "Send to" button on another tool's output to feed its result straight into the original text field here as a starting point for comparison.