ULID Generator Documentation

Generate sortable, timestamp-based ULID identifiers as an alternative to random UUIDs.

SiteIndex encodes the current timestamp and cryptographically random bytes using Crockford's Base32 alphabet to produce a 26-character ULID that sorts naturally by creation time.

• Generate identifiers that sort chronologically in a database index.
• Replace random UUIDs where insertion order matters for performance.
• Generate a batch of test identifiers for seed data.

Input

Text, files, or values entered in the browser, depending on the tool.

Output

A result shown in the browser that can be reviewed or copied where supported.

• The timestamp comes from the device clock. IDs generated in the same millisecond have random tails, not guaranteed monotonic order.
• An identifier is not a password, access token, or uniqueness guarantee.

Inputs for this browser-side tool are processed locally and are not sent to SiteIndex. Normal page analytics may still be collected as described in the Privacy Policy. Read the Privacy Policy.