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Ubify Core Engineering Team
SOFTWARE ENGINEERS & SYSTEMS ARCHITECTS
About This Tool
Universally Unique Identifiers (UUIDs), also known as Globally Unique Identifiers (GUIDs), are 128-bit labels used extensively in distributed software architecture, database primary keys, session identification, and message queue routing. This generator produces standards-compliant RFC 4122 Version 4 random UUIDs directly inside your browser using operating system cryptographic entropy.
### Structure of an RFC 4122 Version 4 UUID
A Version 4 UUID contains 128 bits displayed as 32 hexadecimal characters separated by four hyphens into an 8-4-4-4-12 pattern (`xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx`): - **Version Bits:** The four-bit field at index 14 is hardcoded to `4` (binary `0100`), indicating a random or pseudorandom UUID. - **Variant Bits:** The two-bit field at index 19 holds the variant pattern `10` (represented by hex characters `8`, `9`, `a`, or `b`), declaring compliance with the Leach-Salz variant standard. - **Random Entropy:** The remaining 122 bits draw raw cryptographic randomness via browser `crypto.randomUUID()`, providing an astronomical collision space of $2^{122} \approx 5.3 \times 10^{36}$ unique identifiers.
### Worked Generation Example
Drawing a fresh Version 4 UUID: - **Raw Generated String:** `f47ac10b-58cc-4372-a567-0e02b2c3d479` - **Structure Breakdown:** - Time-low & mid: `f47ac10b-58cc` - Version & time-high: `4372` (begins with `4`) - Variant & clock-seq: `a567` (begins with `a`) - Node identifier: `0e02b2c3d479` - Clicking copy saves the sanitized lowercase UUID string directly to your clipboard.
### Zero Network Transmission Guarantee
All UUID generation occurs strictly within local browser memory using the native Web Cryptography API. Generated identifiers are never uploaded to remote servers, logged in cloud analytics, or cached in external databases.
How to Use
- 1
Click "Generate UUID" to produce a cryptographically random RFC 4122 Version 4 identifier.
- 2
Toggle uppercase or lowercase representation according to your database conventions.
- 3
Generate multiple UUIDs at once using the bulk count selector.
- 4
Click the copy icon to transfer the generated UUIDs directly into your application code or database schema.
Frequently Asked Questions
What is the probability of two Version 4 UUIDs colliding?
With 122 bits of raw entropy, generating 1 billion UUIDs per second for 100 years carries less than a one in a billion probability of generating a single collision.
What is the difference between a UUID and a GUID?
UUID (Universally Unique Identifier) is the open IETF RFC 4122 standard term, while GUID (Globally Unique Identifier) is Microsoft's historical implementation of the exact same 128-bit structure.
Are these identifiers generated using secure hardware entropy?
Yes. Modern browsers execute crypto.randomUUID() by querying your host operating system's cryptographic pseudo-random number generator (CSPRNG), avoiding the predictability risks of Math.random().