NanoID vs UUID

NanoID and UUID v4 compared, side by side.

NanoID vs UUID

What actually differs, and which one to reach for.

NanoID solves a narrower problem than UUID: produce a short, URL-safe, cryptographically random string. It has no version bits, no variant field and no standard behind it - the format is whatever alphabet and length you choose.

NanoID compared with UUID v4
Dimension	NanoID	UUID v4
Default length	21 characters	36 characters with hyphens
Alphabet	Configurable, URL-safe by default	Fixed hexadecimal
Entropy at default size	~126 bits	122 bits
URL-safe without escaping	Yes	Yes, but longer
Standardised	No, a library convention	RFC 4122 / RFC 9562
Sortable	No	No (v4)
Database UUID column	Needs a text column	Native uuid type

When to use NanoID

Short links, invite codes and other identifiers a human might type or share.
Anywhere the identifier appears in a URL and length affects usability.
When you want to exclude look-alike characters from the alphabet.

When to use UUID v4

Database primary keys with a native uuid column type.
Interop with APIs, protocols or tooling that expect a UUID.
When a standardised, self-describing format matters more than length.

Verdict

Use NanoID for user-visible identifiers where the string length is part of the UX, and UUID where a standard format and native database support matter. Shortening a NanoID below about 12 characters raises collision risk quickly, so size it against your expected volume rather than by feel.

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From the maker of MakeUUID

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