UUID Generator
Generate UUID v1, v4, v5, v7, ULID, and Nano ID. Inspect and format UUIDs.
A UUID (Universally Unique Identifier) is a 128-bit identifier represented as 32 hexadecimal digits in the format 8-4-4-4-12. UUIDs are designed to be globally unique without a central authority, making them ideal for distributed systems, database primary keys, session identifiers, and API resources.
There are several UUID versions, each with distinct characteristics. UUID v4 generates fully random identifiers and is the most widely used version due to its simplicity and excellent uniqueness guarantees. UUID v1 includes a timestamp and the device MAC address, allowing chronological sorting but potentially revealing system information. UUID v5 generates deterministic identifiers based on a namespace and name using SHA-1, useful when you need the same UUID for the same input.
UUID v7 is the newest addition defined in RFC 9562, specifically designed to be time-sortable. It combines a Unix millisecond timestamp with random bits, offering the advantages of UUID v4 (randomness) with the ability to sort by time. This makes it especially suitable as a database primary key where insertion order impacts performance.
ULID (Universally Unique Lexicographically Sortable Identifier) is an alternative to UUID that encodes a 48-bit timestamp and 80 random bits in Crockford Base32, producing a 26-character string. ULIDs are more compact than UUIDs and can be sorted by creation time, making them popular in modern applications.
Nano ID is another unique identifier generator that produces shorter and customizable strings. It allows you to configure the length and alphabet used, providing flexibility for cases where standard UUIDs are too long. This tool processes everything in your browser, ensuring the privacy of generated identifiers.
Frequently Asked Questions
A UUID (Universally Unique Identifier) is a 128-bit identifier represented as 32 hexadecimal digits in the format 8-4-4-4-12 (e.g., 550e8400-e29b-41d4-a716-446655440000). UUIDs are designed to be globally unique without a central authority.
For most applications, UUID v4 (random) is the best choice due to its simplicity and strong uniqueness guarantees. If you need time-sortable IDs (e.g., for database primary keys), use UUID v7 (new RFC 9562 standard) or ULID. UUID v1 contains MAC address info and is rarely recommended.
A ULID (Universally Unique Lexicographically Sortable Identifier) is an alternative to UUID that encodes a 48-bit timestamp and 80 random bits in Crockford Base32, producing a 26-character string. ULIDs are sortable by creation time and more compact than UUIDs.