UUID v4 vs Nano ID
UUID v4 or Nano ID for identifiers? Length, collision risk and URL-friendliness compared.
Reviewed by The Markvibe Team · Last updated 2026-06-28
UUID v4 is the RFC 4122 standard for random identifiers — 128 bits, 36 characters with hyphens. Nano ID is a modern alternative that fits more entropy into fewer characters using a URL-friendly alphabet. For pure size and shareability Nano ID wins; for ecosystem interoperability UUID still wins.
Side-by-side comparison
| Feature | UUID v4 | Nano ID |
|---|---|---|
| Default length | 36 chars | 21 chars |
| Entropy | 122 bits | 126 bits |
| URL-safe | Yes (after stripping hyphens) | Yes natively |
| Database support | Native uuid type everywhere | Stored as text |
| Spec | RFC 4122 | Library convention |
Our recommendation
Use UUID v4 when interop with databases, message queues and SDKs matters. Use Nano ID for short, URL-friendly public identifiers.
Try
UUID v4 tool →
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