Pre-configured tool settings you can use, save, and share with others.
A preset is a saved configuration for one tool: the regular expression and flags you keep retyping, the indentation and key order you always want out of a formatter, the character set and length you use when generating a password. Open the tool through a preset and those settings are already in place.
The point is repetition. A pattern you write once is not worth saving. A pattern you rebuild from memory every second week, slightly differently each time, is exactly what this is for, and having it written down means the version you use is the version you already got right.
Twelve presets are built in and available without an account. Four are regular expressions people rewrite constantly: an email pattern, a matcher for HTTP and HTTPS URLs, an IPv4 address, and a US phone number. Three cover formatting: two-space and four-space indentation, and JSON with its keys sorted so two generated files can be compared.
The rest are task shaped rather than setting shaped: cleaning noise out of server logs, pulling every email address out of a block of text, decoding a token for debugging, and two password recipes, one for a strong random password and one for a numeric PIN.
Your own presets are grouped into the same categories as the built-in ones: regular expressions, JSON, text transformation, encoding, validation, and anything else as custom. They are kept in your own browser first, so they work without signing in, and they sync to your account when you are signed in so a second machine sees them too.
Sharing works through a link rather than an account. A preset is encoded into the URL itself, so sending it to somebody is sending them a link, and opening that link offers to import it. Nothing has to be published anywhere for a teammate to use your configuration. Free accounts keep up to five saved presets and Pro raises that to a hundred; teams get a shared list on top of the personal one.
Browse the full tool directory to see which tools you use often enough to be worth a preset.