ULID Unique ID Generator

Generate ULIDs (Universally Unique Lexicographically Sortable Identifiers) online. ULIDs are 128-bit identifiers that are URL-safe, sortable by time, and compatible with UUID. Ideal as database primary keys.

How to Use

1. Step 1: Click Generate to create a new ULID.
2. Step 2: Generate multiple ULIDs using the count input.
3. Step 3: Click Copy to copy the ULID(s).

Frequently Asked Questions

What is a ULID?

A ULID (Universally Unique Lexicographically Sortable Identifier) is a 128-bit identifier that encodes a timestamp and random component.

What is the advantage of ULID over UUID?

ULIDs are sortable by creation time unlike UUID v4, URL-safe, and more compact (26 chars vs 36 for UUID).

What are the advantages of ULID over UUID?

ULID advantages include: 1) Lexicographically sortable by creation time; 2) URL-safe Base32 encoding with no need for escaping; 3) More compact at 26 characters vs 36 for UUID with hyphens; 4) More readable. The trade-off is time dependency — two ULIDs generated within the same millisecond retain random ordering among themselves.

What are the trade-offs between ULID and UUID v4?

ULID advantages: timestamp prefix makes it naturally time-ordered (more B-tree index friendly, fewer page splits); shorter string form (26 chars vs. 36 for UUID); URL-safe (uppercase letters and digits only). UUID v4 advantages: more widely supported with mature library ecosystems; fully random with no time information leakage concerns. Usage: prefer ULID for database primary keys and IDs that need ordering; use UUID v4 for fully random IDs where ordering does not matter.