Security & Crypto

ULID + NanoID Generator

Generate bulk ULIDs with optional monotonic mode and custom timestamps, or NanoIDs with any alphabet and length. Decode any ULID to inspect its timestamp + randomness; compute collision probability for any NanoID configuration.

About ULID

A ULID is a 26-character Crockford base32 string. The first 10 characters encode the creation time in milliseconds (so two ULIDs sort correctly by time) and the remaining 16 are 80 bits of randomness. Designed to be safe for URLs, lexicographically sortable, and a drop-in alternative to UUID v4.

Bulk generate ULIDs

Draw between 1 and 1000 ULIDs at a time. Pick a custom timestamp to backfill historical IDs.

Count

Between 1 and 1000.

Use current timestamp

Monotonic modeWithin the same millisecond, increment the random portion by 1 instead of redrawing.

Output · 10

0101KT2A709P1PGQ2MG8YN482H36
0201KT2A709PB7S0NVZAVXWA8MY2
0301KT2A709P29YHBNAX2YBWCBFJ
0401KT2A709P6N65XV407ESC82FX
0501KT2A709P28EYFQ68BNDEHBCZ
0601KT2A709PDKCPGMT9ZKDK21NW
0701KT2A709PF67M0WNBJD11EXFY
0801KT2A709P7F51YG84HMWFX771
0901KT2A709Q7JC5Z6E34FKBGR37
1001KT2A709QJ9X8XH7KBP21RNTG

ULID decoder

Paste any ULID to see its embedded timestamp and randomness.

ULID to decode

Validity

—

Timestamp (ms)

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Timestamp (ISO)

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Randomness (base32)

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Randomness (hex)

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Compare two ULIDs

Lexicographic order matches creation time — paste two ULIDs to see which is older.

ULID A

ULID B