Nano ID generator

Generates 21-character URL-safe identifiers. A Nano ID has about 126 bits of entropy — slightly more than a v4 UUID — in 21 characters rather than 36.

The saving comes from the alphabet: 64 URL-safe characters against a UUID’s 16 hexadecimal ones, so each character carries six bits instead of four. That makes it a better fit anywhere the identifier appears in a URL or is read aloud, and the shorter string genuinely matters at scale in URLs and log lines. What it does not have is any structure — no version, no timestamp, no sortability — so it is the wrong choice for a database primary key where insert locality matters, and the right choice for a public-facing share link.