UUID / ULID Generator

Instantly generate RFC-compliant UUID v4 or ULID identifiers in bulk. Cryptographically secure, 100% client-side.

Used 1,233 times

Type

Count

Case

UUID vs ULID

UUID v4

  • 128-bit random identifier
  • Format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
  • RFC 4122 compliant
  • Widely supported across all databases & languages
  • Not sortable by generation time
  • ~5.3 × 1036 possible values

ULID

  • 128-bit: 48-bit timestamp + 80-bit random
  • Format: 26-char Crockford Base32 string
  • Lexicographically sortable (newest last)
  • Monotonic within the same millisecond
  • URL-safe, no hyphens
  • Ideal for time-ordered database primary keys

When to Use Each

  • UUID v4 — general-purpose IDs, tokens, session IDs where order doesn't matter
  • ULID — database primary keys where you want to avoid index fragmentation and keep insertion order
  • Both are cryptographically secure via crypto.getRandomValues()
  • All generation happens in your browser — nothing is sent to any server

Hash Generator

MD5, SHA-256, SHA-512 from any text

Base64 Encoder

Encode and decode Base64 strings

All Free Tools

Explore our full collection of developer tools — no login, no limits.

JSON Formatter Base64 Encoder/Decoder URL Encoder/Decoder Color Converter Timestamp Converter Password Generator Word Counter Hash Generator CSS Minifier HTML Formatter Markdown to HTML JWT Decoder Image to Base64 Regex Tester