UUID Generator
Generate random v4 UUIDs in bulk
UUID Generator: Universally Unique Identifiers
The standard for collision-free IDs — 128 bits of pure randomness.
A UUID (Universally Unique Identifier) is the standard way to mint unique IDs without asking a central authority: database primary keys, API resource IDs, file names, session tokens... The most common version, v4, uses 122 bits of pure randomness — the space of possible IDs is so vast that collisions are practically impossible. This tool generates up to 100 UUIDs at once using your browser's cryptographically secure generator (crypto.randomUUID), with lowercase, UPPERCASE and no-dash format options. Generation happens entirely on your device; nothing is recorded anywhere — every visit gives you fresh, unrepeatable values.
Features
True Randomness
crypto.randomUUID — cryptographically secure.
Bulk Generation
Up to 100 UUIDs with one click.
Format Options
Lowercase, UPPERCASE or dash-free.
Copy All
Grab the whole list with one click.
UUID Guide
Structure & versions
- Format: 8-4-4-4-12 hex digits, 36 characters total
- The 3rd block's first digit reveals the version: 4xxx = v4
- v4: fully random — the most common version
- v7: time-ordered (newer standard, database-friendly)
Where they're used
- Database primary keys (in distributed systems)
- API resource IDs and request tracing
- File/object naming without collisions
- Session and device identifiers
Frequently Asked Questions
Is the collision probability really zero?
Not mathematically, but practically yes: v4 has 2¹²² possibilities. Generating a billion UUIDs per second, you'd need about 85 years to reach a 50% collision chance — which is why nobody checks for existence before generating.
Are UUID and GUID the same thing?
Yes — GUID (Globally Unique Identifier) is Microsoft's name for the same standard. Format and generation are identical; the .NET world says GUID, everyone else says UUID.
What's the difference between v4 and v7?
v4 is fully random; v7 starts with a timestamp, so values sort by creation time. v7 is rising in new systems because it performs better in database indexes; v4 remains the most common and compatible.
Should I use UUIDs as primary keys?
Very much so in distributed systems and whenever clients must mint IDs. The one drawback: random v4s grow B-tree indexes untidily — under heavy write load consider v7 or ULID.
Are generated UUIDs recorded anywhere?
No. Generation runs in your browser; no ID is sent to or stored on any server. The list lives only on your screen until you copy it.
When is the dash-free format useful?
Some systems (legacy database schemas, URL constraints, certain APIs) want the 32-digit dash-free form. The content is identical — it's purely a display difference, convertible both ways without loss.