UUID Generator vs NanoID Generator

UUID v4 and NanoID are both widely-used unique identifier generators, but they differ in format, length, and collision probability.

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UUID Generator

UUID generator — create UUID v4 (cryptographically random) or UUID v7 (time-ordered, RFC 9562) identifiers instantly. Bulk-generate up to 100 UUIDs at once and download as a text file. UUID v7 is ideal for database primary keys — it is lexicographically sortable and avoids index fragmentation.

  • RFC 4122 standard format
  • 36 characters including hyphens
  • 122 bits of randomness
  • Universally supported across all systems
  • Human-readable hyphenated format
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NanoID Generator

NanoID generator — create secure, compact, URL-safe unique IDs using crypto.getRandomValues. Default 21-character IDs have the same collision probability as UUID v4 but are shorter. Configurable alphabet and length.

  • Compact alphanumeric format (customizable)
  • 21 characters by default
  • ~126 bits of randomness at default length
  • URL-safe alphabet by default
  • Smaller than UUID — better for URLs and DBs

When to use each

Use UUID Generator when…

You need a universally recognized standard format, database compatibility, or interoperability with external systems.

Use NanoID Generator when…

You need short IDs for URLs, database keys, or anywhere where character count matters and you control both ends.