Comparing two texts line by line

Finding what changed between two versions of a file by eye is tedious and unreliable. A diff tool does the work for you: it aligns the two texts and highlights added, removed or changed lines.

Reading a diff

The convention is simple: lines present on the left but not the right were removed, those present only on the right were added, and a change shows up as a removal followed by an addition. Identical lines act as anchors to place the change in context.

💡 Anecdote - The most common diff algorithm (Myers, 1986) is the work of Eugene Myers, who would later lead the computational assembly of the human genome.

When it helps

• Check what a copy-paste actually changed
• Compare two exports, two configs, two API responses
• Review a translation or an edit before approving it

Without sending anything

Comparing files can reveal sensitive data - keys, credentials, private content. Our text compare tool computes everything in the browser: the two versions never leave your machine, so you can diff confidential content safely

🤓 Did you know? The diff algorithm was designed at Bell Labs in 1976, partly by Doug McIlroy - the same person who invented Unix pipes (the | character).