Generate random v4 UUIDs with multiple format options
Generate and inspect unique identifiers across six common schemes: UUID v4 (random, via the browser crypto.randomUUID), UUID v1 (timestamp plus node), ULID (26-character Crockford Base32, lexicographically sortable), NanoID (URL-safe, customizable length), CUID (collision-resistant, prefixed with c), and Snowflake (Twitter-style 64-bit IDs that pack a timestamp, datacenter ID, worker ID, and sequence). Pick a type, set a count for bulk generation, and copy individually or all at once. A separate Validate & Parse mode takes any ID you paste, auto-detects its format, and breaks it down, including pulling the embedded timestamp out of UUID v1 and ULID, and decoding the timestamp, datacenter ID, worker ID, and sequence number from a Snowflake ID.
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You need a batch of collision-safe identifiers for new database rows generated client-side before insert.
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Version 4 · quantity 3
Generated UUIDs
f47ac10b-58cc-4372-a567-0e02b2c3d479 9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d 3f333df6-90a4-4fda-8dd3-9485d27cee36
A v4 UUID is 122 random bits (the `4` marks the version, and the `8/9/a/b` nibble marks the variant), giving a collision probability so small you can generate them independently on many clients without coordination. Randomness comes from the Web Crypto CSPRNG, so values are not predictable across requests.
Generate and inspect unique identifiers across six common schemes: UUID v4 (random, via the browser crypto.randomUUID), UUID v1 (timestamp plus node), ULID (26-character Crockford Base32, lexicographically sortable), NanoID (URL-safe, customizable length), CUID (collision-resistant, prefixed with c), and Snowflake (Twitter-style 64-bit IDs that pack a timestamp, datacenter ID, worker ID, and sequence). Pick a type, set a count for bulk generation, and copy individually or all at once. A separate Validate & Parse mode takes any ID you paste, auto-detects its format, and breaks it down, including pulling the embedded timestamp out of UUID v1 and ULID, and decoding the timestamp, datacenter ID, worker ID, and sequence number from a Snowflake ID.
The six ID types solve different problems. UUID v4 is 122 random bits and is the safe default when you just need a unique value and do not care about ordering. UUID v1 and ULID and Snowflake are time-ordered, so newly generated IDs sort roughly by creation time, which is useful as database primary keys because it keeps index inserts near the end of the B-tree instead of scattering them. ULID and NanoID are more compact than a 36-character UUID: ULID is 26 characters of Crockford Base32 (no I, L, O, or U to avoid ambiguity), and NanoID defaults to 21 URL-safe characters but you can shorten or lengthen it here. CUID is designed to be collision-resistant in distributed clients, and Snowflake encodes infrastructure metadata directly in the number.
The Validate & Parse mode is the part most generators skip. Paste a UUID and it confirms the version and the RFC 4122 variant; paste a UUID v1 and it reconstructs the 100-nanosecond timestamp and shows the real date; paste a 26-character ULID and it decodes the leading 48-bit timestamp; paste a Snowflake ID and it shifts out the timestamp (relative to the Twitter epoch), datacenter ID, worker ID, and sequence. It also accepts a dashless 32-hex-character UUID and reformats it into canonical 8-4-4-4-12 form. Optional prefix and suffix fields (for example user_ or _v1), an uppercase toggle, and a no-dashes toggle let you shape UUID output to match your codebase conventions. Everything runs in your browser.
UUID v4 is the safe default for general unique IDs. Choose a time-ordered type (UUID v1, ULID, or Snowflake) when you want IDs that sort by creation time, ULID or NanoID when you want a shorter string, and Snowflake when you need infrastructure metadata packed into a 64-bit number.
Practically no. The probability of a collision with v4 UUIDs is astronomically low, you would need to generate over a billion UUIDs per second for decades to have a 50% chance of one duplicate.
Yes. Switch to Validate & Parse mode and paste the ID. The tool detects whether it is a UUID (and which version), a ULID, a Snowflake, or a CUID, and shows any timestamp or metadata encoded inside it.
A UUID is a 128-bit value displayed as 32 hexadecimal digits in five groups separated by hyphens: 8-4-4-4-12 (e.g., 550e8400-e29b-41d4-a716-446655440000).
Conversions run on your device in JavaScript. The values you enter are never sent over the network.