GUID/UUID Generator
Generate RFC 4122 compliant unique identifiers instantly
Random-based UUID (most common)
Click "Generate UUID" to create unique identifiers
What is a UUID/GUID?
A UUID (Universally Unique Identifier) or GUID (Globally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. The probability of generating duplicate UUIDs is so small that it's considered negligible for practical purposes.
UUIDs are standardized by RFC 4122 and newer specifications (RFC 9562 for v6-v8). The format consists of 32 hexadecimal digits displayed in five groups separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters (32 alphanumeric characters and 4 hyphens).
UUID Version Types
Version 4 (Random)
The most commonly used version. UUID v4 is generated using random or pseudo-random numbers. This provides excellent uniqueness with minimal overhead and is ideal for most applications where you need unique identifiers without specific ordering requirements.
Version 7 (Unix Timestamp + Random)
The newest and recommended version for most use cases. UUID v7 combines Unix timestamp (millisecond precision) with random data, providing both uniqueness and sortability. Ideal for database primary keys as they maintain chronological order while being globally unique.
Version 1 (Timestamp + MAC)
Generated using a timestamp and the MAC address of the computer. UUID v1 guarantees uniqueness across space and time. Note that MAC addresses can potentially identify the generating machine, which may be a privacy concern in some applications.
Version 6 (Reordered Time)
A reordered version of UUID v1 that places the timestamp in a more sortable format. The high bits of the timestamp come first, making these UUIDs naturally sortable by creation time while maintaining compatibility with v1's timestamp-based approach.
Version 8 (Custom/Experimental)
Allows for custom UUID formats with application-specific data. This version is designed for applications that need specific information encoded in the UUID format while maintaining the standard UUID structure. You can optionally add a custom prefix (like "USER" or "PROD") that gets encoded into the UUID. Useful for domain-specific requirements where you want to embed metadata.
Nil UUID
A special UUID with all bits set to zero (00000000-0000-0000-0000-000000000000). Used as a placeholder or to represent an empty/null UUID value in applications and databases.
Common Use Cases
Database Primary Keys
Use UUIDs (especially v7) as primary keys in distributed databases to avoid conflicts when merging data from multiple sources while maintaining sortability
Session Identifiers
Generate unique session IDs for web applications and APIs to track user sessions securely with minimal collision risk
Distributed Systems
Identify resources across microservices and distributed architectures without central coordination
Custom Application Identifiers
Use UUID v8 to encode application-specific metadata (like environment, tenant ID, or resource type) directly into unique identifiers