ULID Generator
A ULID Generator produces Universally Unique Lexicographically Sortable Identifiers — 128-bit identifiers encoded as 26 Crockford base32 characters, sorted by time and safer for URL use than UUIDs — using the browser's CSPRNG with zero network traffic.
Time-ordered, URL-safe, 26-char Crockford base32. The leading 10 chars encode a millisecond timestamp; the trailing 16 are pulled from crypto.getRandomValues.
About ULID Generator
ULIDs encode a 48-bit millisecond timestamp followed by 80 bits of randomness in a single 26-character string. They're case-insensitive, URL-safe, monotonically increasing within the same millisecond when generated together, and lexicographically sortable. Pick a quantity, toggle uppercase, and copy or download the list. The generator uses crypto.getRandomValues for the random portion.
What ULID Generator does
- Generate up to 1,000 ULIDs (128-bit, 26-char Crockford base32) at a time
- 48-bit ms timestamp + 80 bits of CSPRNG randomness
- Monotonic mode for guaranteed sortability within the same millisecond
- Uppercase / lowercase toggle
- Bulk copy as a newline-delimited list or JSON array
When to reach for ULID Generator
- Primary keys that stay close on disk for B-tree-friendly insert performance
- Time-ordered event IDs for audit logs and ledgers
- URL-safe identifiers that double-click-select cleanly
- Replacing UUID v4 keys in a schema you can still freely migrate
How to use ULID Generator
- 01
Pick a quantity
Enter how many ULIDs you need (1 to 1,000).
- 02
Toggle monotonic mode
On by default — guarantees lexicographic ordering even within a single millisecond.
- 03
Copy the list
Click Copy to grab the entire batch as newline-delimited text.
When to use ULID Generator vs alternatives
| Alternative | Use ULID Generator when… | Use the alternative when… |
|---|---|---|
| UUID v4 | you want time-ordered, lexicographically sortable IDs friendly to B-tree indexes. | you specifically want no timestamp leak in the ID. |
| Snowflake / KSUID | you want a widely-supported standard with no server coordination. | you need a coordinator-assigned ID that strictly orders across nodes. |
Frequently asked questions
How is a ULID different from a UUID?
Are ULIDs safe to expose in URLs?
Will two ULIDs ever collide?
Related tools
Related concepts
ULID
A ULID (Universally Unique Lexicographically Sortable Identifier) is a 128-bit identifier encoded as 26 Crockford base32 characters that is sorted by time when generated, making it a drop-in replacement for UUID v4 with much better database insert performance.
UUID
A UUID (Universally Unique Identifier) is a 128-bit value, usually written as 32 hex digits in the canonical 8-4-4-4-12 grouping (e.g. '550e8400-e29b-41d4-a716-446655440000'), used as a globally unique ID that any computer can generate without coordination.