UUID and Nano ID both generate collision-resistant unique identifiers, but Nano ID is a compact, URL-friendly random string with a configurable alphabet and length, while UUID is the fixed 128-bit standard. The right choice depends on whether you value standardization or a shorter, tunable ID.
Key takeaways
- UUID is a 128-bit standard; Nano ID is a configurable random string.
- Nano ID is shorter (21 chars by default) and URL-safe out of the box.
- Choose UUID for standards and native DB types; Nano ID for compact public IDs.
What Nano ID is
Nano ID is a small library that generates unique string identifiers from a URL-safe alphabet. By default it produces 21 characters from a 64-symbol alphabet (A-Z, a-z, 0-9, plus - and _), which gives a collision resistance comparable to UUID v4 while being noticeably shorter.
Both the length and the alphabet are configurable, so you can trade length for collision resistance or restrict the character set to avoid ambiguous characters.
How they compare
A UUID is always 128 bits and, in text form, 36 characters with hyphens. A default Nano ID packs similar randomness into 21 characters and needs no hyphens or special formatting to be safe in URLs. UUID wins on universality and native database support; Nano ID wins on compactness and flexibility.
| Aspect | UUID v4 | Nano ID (default) |
|---|---|---|
| Text length | 36 chars | 21 chars |
| Alphabet | Hex + hyphens | URL-safe 64-symbol |
| Configurable | No | Length and alphabet |
| Standardized | Yes (RFC 9562) | No |
| Native DB type | Common | Stored as text |
When to choose each
Choose UUID when you want a standardized identifier, a native database UUID type, or interoperability with tools that already understand UUIDs. Choose Nano ID when you want a shorter, URL-friendly public identifier and you control both ends of the system.
If your main goal was a shorter UUID specifically, also look at encoding a UUID in a more compact form rather than switching identifier systems entirely.