🆔 UUID Gen
Generate random UUID v4 identifiers free online. Cryptographically random, collision-resistant, instant, no upload needed.
🆔 UUID Gen
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About the UUID Gen Tool
A UUID is a 128-bit identifier designed to be unique without any central coordination. That property is what makes it valuable in distributed systems — two servers can generate identifiers simultaneously, with no communication between them, and the chance of collision is negligible.
Version 4 UUIDs are randomly generated, using 122 bits of randomness. The collision probability is small enough that you would need to generate billions per second for decades before it became a practical concern. This generator uses your browser’s cryptographic random source, running entirely on your device.
How to Use UUID Gen
- Press Generate to produce a random UUID v4.
- Generate additional identifiers as needed.
- Copy the value.
- Use it as a database key, correlation ID, or unique reference.
When to Use This Tool
- Generating primary keys for a distributed database
- Creating correlation IDs for tracing requests across services
- Producing unique filenames to prevent collisions
- Generating session or transaction identifiers
- Creating test data with guaranteed unique keys
Things Worth Knowing
- UUID v4 uses random generation. Other versions encode timestamps or namespaces instead.
- The standard format is 36 characters: 32 hexadecimal digits in five groups separated by hyphens.
- UUIDs are unique but not secret — they are predictable enough in structure that they should not be used as security tokens on their own.
Quick Facts
| Tool name | UUID Gen |
| Category | Utilities |
| Price | Free — no account, no trial, no watermark |
| Where it runs | Entirely in your browser (client-side) |
| Files uploaded | None — your data never leaves your device |
| File size limit | None imposed; limited only by device memory |
| Works offline | Yes, once the page has loaded |
| Platforms | Windows, macOS, Linux, Android, iOS |
Frequently Asked Questions
What is the chance of two UUIDs colliding?
Vanishingly small. With 122 random bits, you would need to generate roughly a billion UUIDs per second for about 85 years to reach a 50% chance of a single collision.
Should I use a UUID as a database primary key?
It depends on the database. UUIDs let you generate keys client-side without a round trip, which is valuable in distributed systems. However, random UUIDs fragment B-tree indexes and hurt insert performance in some engines — UUIDv7 or ULID address this by being time-ordered.
What is the difference between UUID and GUID?
Practically nothing. GUID is Microsoft’s name for the same 128-bit identifier standard. The terms are used interchangeably.
Are UUIDs secure enough to use as access tokens?
Not alone. Version 4 UUIDs are cryptographically random, so they are hard to guess, but they are often logged, appear in URLs, and are not designed as secrets. Use purpose-built tokens for authentication.