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How to Generate UUIDs and ULIDs
The UUID/ULID Generator creates random UUIDs (v4) and Universally Unique Lexicographically Sortable Identifiers (ULIDs) — individually or in bulk.
- Choose UUID v4 or ULID format.
- Set the quantity (1 to 100) and click Generate.
- Copy individual IDs or the entire batch.
UUID vs ULID
A UUID v4 is a 128-bit random identifier formatted as 8-4-4-4-12 hex digits (e.g., 550e8400-e29b-41d4-a716-446655440000). A ULID is also 128 bits but encodes a millisecond timestamp in the first 48 bits followed by 80 random bits, making ULIDs lexicographically sortable by creation time. ULIDs are preferred for database primary keys because they maintain insertion order and avoid index fragmentation.
Why Use Our ID Generator?
- UUID and ULID — both formats in one tool.
- Bulk generation — create up to 100 IDs at once.
- Cryptographically random — uses crypto.getRandomValues() for true randomness.
- No server — generation is instant and local.
Frequently Asked Questions
When should I use ULID instead of UUID?
Use ULID when you need sortable IDs (e.g., database primary keys, event logs). The embedded timestamp means ULIDs sort chronologically, reducing index fragmentation in B-tree databases.
Can UUIDs collide?
Theoretically yes, but the probability is astronomically low — roughly 1 in 2^122. In practice, UUID v4 collisions are not a concern.
Are these IDs cryptographically secure?
They use the browser's crypto.getRandomValues(), which is a cryptographically secure random number generator. However, UUIDs and ULIDs are identifiers, not secrets.
Is any data sent to a server?
No. All generation happens locally in your browser.