Generate UUID v1, v4, v5, ULID, CUID, NanoID, ObjectID in bulk. Validate, format, copy and export — free, no signup.
KJSynthora's UUID Generator lets you create any type of unique identifier instantly in your browser — UUID v4, v1, v5, ULID, CUID, NanoID, MongoDB ObjectID and ShortID. Generate one or 10,000 at once, format them, validate existing IDs, and export as TXT, CSV, or JSON.
| Type | Length | Sortable | Random | Deterministic | URL-safe | Best For |
|---|---|---|---|---|---|---|
| UUID v4 | 36 chars | No | Yes | No | No (hyphens) | General unique IDs, DB keys |
| UUID v1 | 36 chars | By time | Partial | No | No | Time-ordered records |
| UUID v5 | 36 chars | No | No | Yes | No | Deterministic IDs from names |
| ULID | 26 chars | Yes | Yes | No | Yes | Database primary keys |
| CUID | ~25 chars | Approx | Yes | No | Yes | Distributed systems |
| NanoID | 21 chars | No | Yes | No | Yes | URLs, short tokens |
| ObjectID | 24 chars | By time | Partial | No | Hex only | MongoDB documents |
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information. The standard format is 8-4-4-4-12 hexadecimal digits separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. UUIDs are used as database primary keys, session IDs, file names, and API tokens.
UUID v4 is randomly generated using a cryptographically secure random number generator — each UUID is unique with overwhelming probability. UUID v1 encodes the current timestamp plus the device's MAC address. v1 UUIDs are time-sortable but they expose system information. v4 is recommended for most use cases where privacy matters.
ULID (Universally Unique Lexicographically Sortable Identifier) is a 26-character ID that encodes a millisecond timestamp plus 80 bits of randomness. Unlike UUID v4, ULIDs are naturally sortable — records sort chronologically by their ID. Use ULID when you need unique IDs that sort by creation time in databases like PostgreSQL, MySQL or DynamoDB.
UUID v4 uses 122 random bits (2^122 ≈ 5.3 × 10^36 possible values). If you generated 1 billion UUIDs per second for 100 years, the probability of a single collision is approximately 50%. For all practical purposes in any system, UUID v4 is unique.
Yes. Enter a count from 1 to 10,000 in the Count field and click Generate. All IDs are generated instantly in your browser. Export them as TXT (one per line), CSV (with index column), or JSON array. You can also use the ×10, ×100, ×1000 quick buttons.
Switch to the Validate tab, paste your UUID (or multiple UUIDs, one per line), and click Validate. The tool checks the format against the UUID RFC, identifies the version (v1, v3, v4, v5), checks the variant bits, and shows whether the format is valid.
NanoID is a tiny URL-friendly unique string ID. It is 21 characters by default using a URL-safe alphabet (A-Za-z0-9_-). It is smaller than UUID and configurable — you can change the length and alphabet. NanoID is popular in JavaScript/Node.js projects for URL slugs, session tokens, and database keys.
Yes, completely free. No signup, no rate limit, no watermark. All UUID generation happens using the browser's built-in crypto.randomUUID() and Web Crypto API — nothing is sent to any server.