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ULID Generator

Network

Generate Universally Unique Lexicographically Sortable Identifiers

A ULID packs a millisecond timestamp into its first 48 bits followed by random bits, so IDs generated later always sort lexicographically after earlier ones, the key difference from a v4 UUID, which is fully random and carries no time ordering at all. That makes ULIDs a natural fit as primary keys or event IDs where you want the database's natural sort order to line up with creation time. This tool generates them and also decodes an existing ULID's timestamp component back out, so you can check exactly when a given ID was minted. They're encoded in Crockford's Base32, which avoids visually ambiguous characters and is safe to drop directly into a URL or filename, and the 80 bits of randomness remaining even within the same millisecond makes same-millisecond collisions extremely unlikely at any realistic generation rate. Everything runs locally in the browser.

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How to use ULID Generator

  • 1.Generate a ULID when you need a unique ID that also sorts chronologically, unlike a random UUID v4.
  • 2.Use ULIDs as primary keys or event IDs when you want lexicographic sort order to match creation time in database indexes.
  • 3.Decode an existing ULID's timestamp component to check exactly when it was generated.

Frequently asked questions

How is a ULID different from a UUID?
A ULID encodes a millisecond timestamp in its first 48 bits followed by random bits, so ULIDs generated later always sort after earlier ones — regular UUID v4 is fully random and doesn't sort by time.
Is my data sent anywhere?
No, generation and decoding both happen locally in your browser.
Are ULIDs URL-safe?
Yes, ULIDs use Crockford's Base32 encoding, which avoids ambiguous characters and is safe to use directly in URLs and filenames.
Can two ULIDs generated in the same millisecond collide?
The random portion still has 80 bits of entropy, so collisions within the same millisecond are extremely unlikely at any realistic generation rate.

Use via API, SDK, or MCP

cURL# Free: 1,000 req/day · Pro: 10,000 req/day
curl -X POST https://api.utilix.tech/v1/tools/ulid \
  -H "Authorization: Bearer utx_live_..." \
  -H "Content-Type: application/json" \
  -d '{"count":1}'

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