How is a ULID different from a UUID?

A ULID encodes a millisecond timestamp in its first 10 characters, so ULIDs generated later always sort after earlier ones, unlike random UUIDs.

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ULID Generator

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

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ULID Generator

Batch generate

Generate multiple ULIDs at once; each one sorts after the previous by creation time.

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What is ULID Generator?

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

How it works

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.

Where a network request is required, SiteIndex validates public HTTP/HTTPS targets before making the request.

Common uses

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.

Limitations

Results depend on the browser, network, input, and external service involved.
This tool is informational and does not replace specialist diagnostics or professional advice.

FAQ

How is a ULID different from a UUID?: A ULID encodes a millisecond timestamp in its first 10 characters, so ULIDs generated later always sort after earlier ones, unlike random UUIDs.

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