UUID Generator
Generate cryptographically secure UUIDs, NanoIDs, ULIDs, and custom IDs. Bulk generation, multiple formats, and validation -- all free, no login, 100% in your browser.
Recent UUIDs
Last 20 generated UUIDs (stored in your browser).
No history yet. Click Generate New above.
UUID vs NanoID vs ULID -- Quick Comparison
| Feature | UUID v4 | NanoID | ULID | Short ID |
|---|---|---|---|---|
| Length | 36 chars | 21 chars | 26 chars | 8 chars |
| Format | Hex + dashes | URL-safe | Crockford Base32 | Alphanumeric |
| Sortable | No | No | Yes (by time) | No |
| Collision-safe | Extremely | Extremely | Extremely | Moderate |
| URL-safe | No (dashes) | Yes | Yes | Yes |
| Standard (RFC) | RFC 9562 | No | No | No |
| Best for | Databases/APIs | Short URLs | DB primary keys | User-facing codes |
Frequently Asked Questions
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier practically guaranteed to be unique across all devices and time. The most common version (v4) uses cryptographically secure random numbers. UUIDs are used in databases, APIs, distributed systems, and anywhere you need a unique ID without a central authority.
Is UUID v4 truly random and secure?
Yes. This tool uses the Web Crypto API (crypto.randomUUID or crypto.getRandomValues) which provides cryptographically secure random numbers. UUID v4 has 122 random bits, giving approximately 5.3 x 10^36 possible values. Collisions are virtually impossible.
When should I use UUID vs NanoID vs ULID?
Use UUID v4 for maximum compatibility (databases, APIs, standards). Use NanoID for shorter, URL-safe IDs (21 chars vs 36). Use ULID when you need sortable IDs that encode creation time (great for database primary keys). Use Short IDs for user-facing codes where brevity matters.
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