UUID/ULID Generator

A UUID (Universally Unique Identifier) is a 128-bit identifier that is unique across space and time. UUIDs are commonly used in databases, APIs, and distributed systems to identify resources without requiring a central authority to ensure uniqueness. The standard format is 32 hexadecimal digits displayed in five groups separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.

UUID v1 is timestamp-based, incorporating the current time and a node identifier (typically a MAC address simulation). This makes v1 UUIDs roughly sortable by creation time but potentially reveals information about when they were created. UUID v4 is randomly generated using cryptographically secure random numbers, providing better privacy and unpredictability. V4 is the most commonly used version for general-purpose unique identifiers.

A ULID (Universally Unique Lexicographically Sortable Identifier) is a 26-character identifier that combines a 48-bit timestamp with 80 bits of randomness. Unlike UUIDs, ULIDs are case-insensitive, URL-safe, and lexicographically sortable by creation time. Use ULIDs when you need IDs that can be sorted chronologically, such as for database primary keys where insertion order matters, or when you need shorter, more URL-friendly identifiers.

Yes, for all practical purposes. UUID v4 uses 122 random bits, making the probability of generating duplicate UUIDs astronomically small (about 1 in 5.3 × 10^36). You would need to generate 1 billion UUIDs per second for about 85 years to have a 50% chance of a collision. This makes UUIDs suitable for virtually any application requiring unique identifiers.

Yes, this UUID generator is completely free with no signup required. All UUID generation happens entirely in your browser using JavaScript - no data is sent to any server. This makes it completely safe and private for generating identifiers for any purpose, including sensitive applications.