Free UUID Generator Online
Generate random UUID v4 identifiers instantly. Create single or bulk UUIDs with one click and copy to clipboard.
A UUID (Universally Unique Identifier), sometimes called a GUID, is a 128-bit value designed to be unique across time and space without a central authority issuing it. This tool generates random UUID v4 values, which are produced from your browser's cryptographically secure random number generator and have a roughly 1-in-2^122 chance of colliding — in practice, unique forever. Use the output as a database primary key, a correlation ID in logs, a filename that will not collide, or anywhere you need a unique identifier that does not reveal creation time or ordering. UUIDs are generated locally in your browser; nothing is sent over the network.
UUID Generator
How to use this uuid generator
- Click Generate to produce a single UUID v4.
- To generate multiple at once, set the count and click Generate — each result appears on its own line for easy copy-paste.
- Click Copy to put the UUID (or the whole batch) on your clipboard.
- Paste it into your database seed, configuration file, URL, or wherever you need an identifier.
Common use cases
- Seeding a database with unique primary keys before inserts
- Assigning a correlation or request ID to trace a call through logs and services
- Generating a filename that will not collide with existing files
- Creating an idempotency key for a payment or API request
- Producing short-lived session identifiers or invite tokens
Frequently asked questions
What is UUID v4?
UUID version 4 is a variant generated almost entirely from random bits (six bits are reserved to mark it as v4). It carries no information about the machine, user, or time that produced it, unlike v1. Because it has 122 bits of entropy, two independently generated v4 UUIDs are practically guaranteed not to collide.
Can two UUIDs ever be the same?
In theory yes, in practice no. The probability of a collision among a billion UUIDs is lower than the probability of a hardware memory error corrupting the comparison. You do not need to check for uniqueness before inserting a random UUID into a database.
Should I use a UUID as a database primary key?
You can, and it has trade-offs. UUIDs let multiple services generate keys without coordination, which is useful for distributed systems. However, random UUIDs hurt B-tree index locality (inserts scatter across the index), so heavy-write tables sometimes prefer auto-increment integers or time-ordered alternatives like UUIDv7 or ULID.
Are UUIDs safe to expose in URLs?
v4 UUIDs are safe to expose — they leak no information about when or how they were created, and they cannot be guessed in any reasonable time. Do not use them as secrets, though: anyone who sees the URL can share it. For secret tokens, use a dedicated random token, not a UUID.
What is the difference between UUID and GUID?
They are the same thing. GUID (globally unique identifier) is Microsoft's term; UUID is the RFC 4122 term used elsewhere. The format and bit layout are identical — you can paste a GUID into any UUID parser and vice versa.