About fullsduck

A small set of tools for everyday work with text and data, built to be quick, clean and private.

Private by design

Every tool runs in your browser. Text you paste and files you open are processed on your device and are never uploaded. Once a page has loaded it makes no requests of its own, and its security policy blocks connections to other sites.

There are no accounts, cookies, ads, trackers or analytics.

The tools

• Compare text finds the smallest set of changed lines with the Myers algorithm, the one Git uses by default, then marks the changed words inside each changed line.
• JSON formatter checks input with your browser’s own JSON parser, so what passes here passes in JavaScript.
• Encode & decode works on the UTF-8 bytes of your text, so accents, scripts and emoji survive the round trip.
• Hash generator uses the browser’s built-in Web Crypto for SHA-1 and SHA-2. MD5, which Web Crypto lacks, is computed by the page.
• Timestamp converter shows times in UTC and in the time zone your device reports.
• UUID generator takes its randomness from the browser’s cryptographic random number generator.

A note on MD5 and SHA-1

Both are fine for spotting accidental changes, such as a corrupted download, but both are broken against deliberate tampering. Use SHA-256 or stronger whenever security matters.