How do I generate a ULID online?

Enter how many you need above and run the tool. You get ULIDs instantly — 26-character sortable unique IDs, free, no signup, generated in your browser.

What is the difference between ULID and UUID?

Both are 128-bit unique identifiers, but ULIDs are lexicographically sortable by creation time (the timestamp comes first), while UUIDv4 is fully random. ULIDs are also shorter as strings (26 vs 36 chars) and URL-safe without encoding.

Why use ULIDs as database primary keys?

ULID primary keys sort by creation time, which keeps B-tree indexes efficient and makes "latest records" queries fast without a separate timestamp column. They are also safe to expose in URLs, unlike sequential integer IDs.

What is Crockford base32?

Crockford base32 is an encoding that uses 0-9 and A-Z minus the easily confused letters I, L, O, and U. ULIDs use it so IDs are unambiguous when read aloud or typed by hand.

Are ULIDs guaranteed unique?

Practically yes — 80 bits of cryptographic randomness per millisecond makes collisions astronomically unlikely. But unlike coordinated schemes, two machines can theoretically generate the same ULID; for absolute guarantees, keep a database uniqueness constraint.

ULID Generator — Generate Sortable Unique IDs Online

What is Ulid generator?

ULID Generator — Free ULID generator online — generate sortable, unique ULIDs (Universally Unique Lexicographically Sortable Identifiers) in bulk. No signup, runs in your browser.

Each ULID is built per the ULID spec: a 48-bit Unix timestamp in milliseconds (10 base32 chars) followed by 80 bits of cryptographic randomness (16 base32 chars), encoded with the Crockford base32 alphabet (which skips I, L, O, U to avoid visual confusion). Randomness comes from the platform secure random source. Everything runs locally in your browser. Limitation: ULIDs generated in the same millisecond share the timestamp prefix and differ only in the random part — the spec allows this, but they are not guaranteed unique across machines without coordination.

Why use this ulid generator?

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Built for ulid generator

Free ULID generator online — generate sortable, unique ULIDs (Universally Unique Lexicographically Sortable Identifiers) in bulk. No signup, runs in your browser.

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Transparent & honest

Randomness comes from the platform secure random source; the tool does not implement monotonic increment within the same millisecond.

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Private by design

Everything runs in your browser. Your inputs never leave your device.

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Works everywhere

Fully responsive — perfect on desktop, tablet, and mobile. No app needed.

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Regularly updated

Regularly maintained and reviewed to ensure accuracy.

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Free forever

No accounts, no limits, no watermarks. Use ULID Generator as much as you need.

How to use ULID Generator

1Enter how many ULIDs you need (1 to 100; default is 1).
2Run the tool to generate them instantly.
3Copy the ULIDs — each is 26 characters, uppercase, Crockford base32.
4Use them as database keys, filenames, or request IDs.
5Sort them as plain strings — they come out in creation-time order.

What can you do with ULID Generator?

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Good to know

Randomness comes from the platform secure random source; the tool does not implement monotonic increment within the same millisecond.
ULIDs encode the current time — they reveal roughly when they were created.
Uniqueness is probabilistic (80 random bits), not coordinated — enforce uniqueness in your database for critical keys.

How it works

Each ULID is built per the ULID spec: a 48-bit Unix timestamp in milliseconds (10 base32 chars) followed by 80 bits of cryptographic randomness (16 base32 chars), encoded with the Crockford base32 alphabet (which skips I, L, O, U to avoid visual confusion). Randomness comes from the platform secure random source. Everything runs locally in your browser. Limitation: ULIDs generated in the same millisecond share the timestamp prefix and differ only in the random part — the spec allows this, but they are not guaranteed unique across machines without coordination.

Examples

Single ULID

Status: ok — returns one 26-character ULID like 01J9Z8X7Y6W5V4U3T2S1R0Q.

Batch of 5

Status: ok — returns 5 ULIDs, one per line, in ascending sort order.

Too many requested

Status: error — count must be between 1 and 100.

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