UUID Generator — Instant UUID v4 in Your Browser
Generate one or fifty UUIDs — standard, no hyphens, uppercase, braces, or URN format
cfd2113e-8171-45c3-af91-fe4a14f4ddacab636fcf-df98-4d6e-9c30-3e9ef8f12d7faf141900-7fb3-436a-bbab-7c520e4b1a0a5275e4b7-660a-482d-9838-c123c0940f5d112819d8-6805-4e43-9603-54d8bd791365UUID v4 — 122 random bits + 6 version/variant bits. Collision probability is astronomically low — about 1 in 5 undecillion for a billion UUIDs per second over 85 years.
Generated entirely in your browser using crypto.randomUUID() — nothing leaves your device.
Whether you need one UUID for a database primary key or fifty for a seed script, this generator has you covered. Every UUID is v4 — 122 random bits produced by your browser's cryptographically secure random number generator, meaning no server is involved and no generated value is ever logged or stored. Choose your output format and copy individual values or the entire batch in one click. UUID v4 is the most widely used UUID variant. You will find it everywhere: REST API resource identifiers, database row IDs in PostgreSQL and MySQL, primary keys in NoSQL stores like MongoDB, idempotency keys for payment APIs, file upload tokens, session IDs, and test fixture data. The collision probability is so low that you can treat them as globally unique without any coordination with a central authority.
How to Generate UUIDs
Configure your format, set your count, and copy — done in seconds.
Choose your format
Select from five output formats: Standard (8-4-4-4-12 with hyphens), No hyphens (32 hex chars), Uppercase (all caps with hyphens), Braces ({uuid}), or URN (urn:uuid:prefix). Format applies to all generated values at once.
Set the count
Use the + and − buttons or type directly into the count field. You can generate from 1 to 50 UUIDs per batch. The list updates immediately — there is no separate Generate button needed.
Copy one or all
Click the Copy button on any individual row to copy that UUID. Use Copy all N to copy the entire batch as a newline-separated list, ready to paste into a script, a seed file, or a spreadsheet.
Features
UUID v4 — 122 random cryptographic bits per value
Five output formats: standard, no hyphens, uppercase, braces, URN
Generate 1 to 50 UUIDs per batch
Copy individual UUID or entire batch at once
Regenerate button creates a fresh batch with the same settings
Uses browser-native crypto.randomUUID() — nothing sent to any server
No sign-up, no daily limits, works offline once the page loads
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Frequently Asked Questions
What is UUID v4?
UUID v4 (Universally Unique Identifier version 4) is a 128-bit value with 122 random bits and 6 fixed version/variant bits. It is the most common UUID type because it requires no coordination with a registry or clock — each UUID is generated independently from random data, making duplicates statistically impossible in practice.
Is it safe to use these UUIDs in production?
Yes. The generator uses your browser's crypto.randomUUID() function, which draws from the operating system's cryptographically secure random number generator (CSPRNG). This is the same source used by security libraries, making the output suitable for security-sensitive identifiers like session tokens and API keys.
What is the difference between UUID v4 and UUID v1?
UUID v1 is based on the host's MAC address and current timestamp. It can leak information about when and where it was generated. UUID v4 is purely random — it reveals nothing about its origin. For most applications, v4 is preferred because of its privacy and simplicity.
What format should I use for a database primary key?
Standard format (with hyphens) is most common and is native in PostgreSQL (uuid type) and MySQL 8+ (UUID()). No hyphens is useful in some ORMs that store UUIDs as CHAR(32). Uppercase is required by some Windows-targeting APIs. URN format is used in XML and LDAP contexts.
Can I generate UUIDs offline?
Yes. Once the page loads, UUID generation works entirely in your browser with no internet connection required. The crypto.randomUUID() API is a browser built-in that does not make any network requests.