Free Developer Tool · No Sign-up

UUID Generator & Validator (v4 Online)

Generate random UUID v4 identifiers online — free, instant, and private. Bulk-generate up to 100 at once, validate any UUID and detect its version, all with cryptographically secure randomness in your browser.

Generate UUIDs

Version

Count

UppercaseWith braces {...}

Validate UUID

How to Generate a UUID in 3 Steps

1
Pick the version
v4 random is the default and what 95% of use cases need. Time-based and nil UUIDs are one click away.
2
Set the count
Generate 1 for a quick ID or up to 100 for seeding databases and test fixtures.
3
Copy — single or all
One-click copy per UUID, or Copy All for the whole batch. Paste anywhere: code, configs, spreadsheets.

What Is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit ID that is unique across space and time without any central registry — two systems on opposite sides of the world can generate IDs simultaneously with effectively zero collision risk. The standard format is 36 characters: 32 hex digits in five dash-separated groups.

f47ac10b-58cc-4372-a567-0e02b2c3d479

The highlighted 4 marks the version; the a position encodes the variant — that is how the validator reads any UUID.

UUID v4 vs v7 (and v1, v5): Which to Use?

Versions differ in how the 128 bits are filled — random, time-based, or name-hashed:

Version	How it works	When to use it
v1	Time + node based	Legacy systems; leaks timestamp and machine hints
v4	Fully random	The default — general-purpose unique IDs (this tool's main mode)
v5	Name-based (SHA-1)	Deterministic: same input always produces the same UUID
v7	Time-ordered random	Modern DB primary keys — sortable by creation time

Generate UUIDs in Code

Need UUIDs programmatically? Every major language has v4 generation built in — no library required.

JavaScript

crypto.randomUUID()
// 'f47ac10b-58cc-4372-a567-0e02b2c3d479'

Python

import uuid
str(uuid.uuid4())

Java

import java.util.UUID;
UUID.randomUUID().toString();

SQL (Postgres)

SELECT gen_random_uuid();

3 UUID Mistakes to Avoid

Using UUIDs as secrets

UUIDs are identifiers, not passwords — v4 is unguessable in practice, but never rely on an ID for authentication. Use real tokens for auth.

v4 primary keys on huge insert-heavy tables

Random keys fragment database indexes at scale. If insert order matters, v7's time-ordering keeps indexes healthy.

Homemade randomness

Math.random() is not cryptographically secure. Use crypto.randomUUID() or this tool — both use secure system randomness.

Frequently Asked Questions

Is this UUID generator safe and private?

Yes. UUIDs are generated with your browser's Web Crypto API — cryptographically secure randomness, and nothing is ever sent to a server.

Can two UUIDs be the same (collision probability)?

Theoretically possible, practically impossible. A v4 UUID has 122 random bits — you would need to generate about 2.71 quintillion UUIDs to reach a 50% chance of one collision.

What is the difference between UUID v4 and v7?

v4 is fully random; v7 embeds a Unix timestamp so UUIDs sort by creation time. Use v4 for general uniqueness, and v7 for database primary keys where ordered inserts improve index performance.

UUID vs GUID — what's the difference?

They are the same 128-bit identifier. GUID (Globally Unique Identifier) is simply Microsoft's name for UUID — the formats are interchangeable.

What is a UUID used for?

Database primary keys, API request IDs, session tokens, file names, distributed-systems identifiers — anywhere you need an ID that is unique without a central authority coordinating it.

UUID Generator & Validator (v4 Online)

How to Generate a UUID in 3 Steps

Pick the version

Set the count

Copy — single or all