Generate cryptographically secure UUID v4 values instantly. Bulk generate up to 100 UUIDs, copy individually or all at once.
The Logrith UUID Generator creates random, version 4 UUIDs (Universally Unique Identifiers) instantly in your browser — one at a time or in bulk batches of up to 100 at once. UUIDs are widely used in software development as unique identifiers for database records, API resources, session tokens, and distributed systems, and this tool covers generation, formatting, and validation from a single page.
A UUID is a 128-bit value, typically displayed as 32 hexadecimal characters split into five groups separated by hyphens, in the pattern 8-4-4-4-12 — for example, 550e8400-e29b-41d4-a716-446655440000. What makes UUIDs useful is that they can be generated independently, by different systems, at different times, with an astronomically low chance of any two colliding — no central authority or coordination is needed to guarantee uniqueness, which is exactly what makes them so widely used in distributed and decentralized systems.
There are several UUID versions defined by the standard, each generated using a different method. Version 1 UUIDs incorporate the generating computer's MAC address and a timestamp, which means they can theoretically be traced back to the machine that created them. Version 4, which this tool generates, is built entirely from random or pseudo-random numbers instead, with no embedded timestamp or hardware identifier. This makes version 4 UUIDs the most common choice for general-purpose unique identifiers today, since they reveal nothing about when or where they were generated and don't require any special input data beyond a good source of randomness.
A natural question with any random identifier is just how likely a collision actually is. For UUID v4, the math works out to roughly 1 in 5.3 × 10^36 possible values, factoring in the fixed version and variant bits. To put that number in perspective, you'd need to generate over a billion UUIDs every second for about 85 years before there's even a 50% chance of a single collision occurring anywhere. For virtually every practical application, this makes UUID v4 collisions a non-issue — the risk is far smaller than other sources of error in a typical system.
Different systems and languages expect UUIDs in slightly different textual formats, which is why this tool includes five format options. Standard lowercase with hyphens is the most universally recognized format and works as-is in most programming languages and databases. Uppercase is occasionally required by specific legacy systems. No-hyphens format is useful when a system needs a compact 32-character string without separators, such as certain URL slugs. Braces format matches how some Windows and .NET APIs display GUIDs. URN format, prefixed with "urn:uuid:", follows the formal URN namespace defined for UUIDs and is used in some XML, RDF, and semantic web contexts.
All UUID generation and validation in this tool happens locally in your browser using the Web Crypto API — nothing is transmitted to a server, logged, or stored. This makes it safe to use even when generating identifiers for internal systems or sensitive projects, since no record of what you generated exists outside your own browser session.
When designing a new database table or API, picking between a UUID and a simple auto-incrementing integer ID is a common early decision. Auto-increment IDs are smaller, slightly faster to index in some databases, and easy to read at a glance. UUIDs trade some of that simplicity for unpredictability and the ability to generate IDs across multiple servers without coordination. A common middle-ground approach used by many modern systems is to keep an internal auto-increment ID for database performance while exposing a UUID externally in URLs and API responses, getting the benefits of both. Which approach fits best depends on the scale and structure of the system being built, but for anything distributed, public-facing, or merge-sensitive, UUIDs are usually the safer default.