The best free text diff tool compares two blocks of text line by line and shows exactly which lines were added, removed or unchanged, without uploading either version. A browser-based diff computes the comparison on your own device, which makes it safe to use on contracts, configs and code.
The texts people compare are rarely public: contract revisions, configuration files, code that contains keys or internal urls, drafts under embargo. A diff site that processes the comparison on a server receives both full versions of that content. Since diffing is pure computation, there is no technical reason it needs to happen anywhere but your own machine.
Paste the two versions side by side and the tool computes a line-by-line comparison locally, marking each line as added, removed or unchanged. That is enough to spot what changed between two contract drafts, verify an edit did not touch anything else, or review a config change before applying it, instantly and with no account.
No. The diff is computed entirely in your browser, so neither version leaves your device.
Line by line: each line is marked as added, removed or unchanged between the two versions.
Yes. It compares any plain text, and because nothing is transmitted it is safe for code containing secrets.