ToolKitSphereFree Online ULID Generator
Generate Universally Unique Lexicographically Sortable Identifiers (ULID).
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This ULID generator creates Universally Unique Lexicographically Sortable Identifiers directly in your browser. A ULID packs a 48-bit millisecond timestamp and 80 bits of randomness into a single 26-character Crockford Base32 string, which means ULIDs generated later always sort after earlier ones as plain strings — solving a real pain point with random UUID v4 keys, which scatter unpredictably across a database index and hurt insert performance. Backend developers choosing a primary key strategy for high-throughput systems, engineers building event logs or distributed queues where creation order matters, and anyone comparing ULID against UUID v7 will find this generator useful for quick testing. Generation runs entirely client-side using your browser's secure random source — nothing is ever sent to a server. There's no signup, and the tool supports both single and batch generation for seeding test data. If your project specifically needs the RFC 4122 UUID format instead, this platform's UUID generator has you covered too. Scroll down to generate a ULID now.
Features
- Generates standards-compliant 26-character ULIDs
- Combines a 48-bit millisecond timestamp with 80 bits of randomness
- Lexicographically sortable as plain strings
- Crockford Base32 encoding (case-insensitive, no ambiguous characters)
- Batch generation of multiple ULIDs at once
- Fully client-side generation, no server call
- One-click copy to clipboard
- Cryptographically secure randomness via Web Crypto API
Why use this ulid generator (sortable unique id)?
- Instant generation, including in bulk
- Fully private — computed entirely in your browser
- Naturally sortable IDs, better for database index locality than random UUIDs
- Compact, URL-safe, and easy to read compared to hyphenated UUIDs
- Free with unlimited use and no signup
Frequently asked questions
What is a ULID?
A ULID (Universally Unique Lexicographically Sortable Identifier) is a 128-bit identifier combining a millisecond timestamp with random bits, encoded as a 26-character Crockford Base32 string that sorts chronologically.
How is ULID different from UUID?
Unlike random UUID v4, a ULID embeds a timestamp so IDs generated later always sort lexicographically after earlier ones, improving database index performance while remaining effectively unique.
Is a ULID as unique as a UUID?
Yes, practically speaking — a ULID has 80 bits of randomness per millisecond, offering collision resistance comparable to UUID v4 within the same timestamp window.
Why use ULID over an auto-increment integer key?
ULIDs can be generated independently across distributed systems without a central counter, avoiding coordination overhead while still preserving rough chronological ordering.
Does ULID reveal creation time?
Yes, the first 48 bits directly encode a millisecond timestamp, so anyone can extract the approximate creation time from a ULID, which is worth considering for privacy-sensitive identifiers.
What encoding does ULID use?
ULID uses Crockford's Base32 alphabet, which excludes ambiguous characters like I, L, O, and U, and is case-insensitive for easier manual transcription.
Is ULID better than UUID v7?
They solve a similar problem (sortable, time-ordered IDs), and UUID v7 has since been standardized in RFC 9562 as the official IETF answer; the choice often comes down to ecosystem support and format preference.