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UUID generator

Generate cryptographically secure Version 4 (random) and Version 1 (timestamp-based) Universally Unique Identifiers (UUIDs) locally in your browser. Choose your preferred output notation (standard hyphens, uppercase, compact 32-hex, braces, or URN), bulk generate up to 100 UUIDs at a time, download as a text file, and validate existing UUID strings with instant RFC 4122 format inspection.

Generated client-side using Web Crypto API · Zero network requests
First UUID (of 5)
2f63e1f8-35e1-4fbc-91d7-f13301c8856c
Custom count (1 - 100):
Generated UUID List (5)
1.2f63e1f8-35e1-4fbc-91d7-f13301c8856c
2.b617f832-5212-4f96-8b13-5da91454dab2
3.92c9043b-e905-446e-87a1-54bd8f2d046e
4.982e352d-9236-485c-9ab0-89f469de6320
5.65fb5b1a-d50d-43e4-9299-22f979edc8b7

Verify or Inspect Any UUID

UUID generator example

Batch of five UUID v4 keys

Generating 5 random UUIDs in standard lowercase emits identifiers such as 'c4a760a8-dbcf-4e11-be0a-9d9e9d660000', each providing 122 bits of cryptographic entropy.

UUID generator how-to

  1. For UUID v4: generate 16 random bytes using crypto.getRandomValues or native crypto.randomUUID(), setting version bits to 4 (0100) and variant to RFC 4122 (10xx).
  2. For UUID v1: compute 100-nanosecond intervals since October 15, 1582, place into 60-bit timestamp fields, set version 1 (0001), clock sequence (14-bit with 10xx variant), and 48-bit random multicast node ID.
  3. For Nil UUID: emit constant 00000000-0000-0000-0000-000000000000.
  4. Format the 16 bytes into standard 8-4-4-4-12 hexadecimal notation.
  5. Apply formatting transformations: uppercase, strip hyphens, wrap in braces {}, or prepend urn:uuid: as requested.
  6. Repeat for the requested count N and return the collection.

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UUID generator FAQ

What is a UUID generator?
A UUID generator creates RFC 4122 UUIDs such as v4 random and v1 timestamp-based identifiers. This one runs locally in the browser with nothing uploaded.
What is a UUID and which version should I use?
A Universally Unique Identifier (UUID) is a 128-bit label used to uniquely identify resources. UUID Version 4 (v4) is generated from cryptographically secure random numbers and is recommended for almost all applications, databases, and APIs. UUID Version 1 (v1) embeds a high-resolution timestamp.
Are the UUIDs generated here truly random and collision-resistant?
Yes. UUID v4 contains 122 bits of randomness generated by the browser's cryptographic random number generator (crypto.randomUUID / crypto.getRandomValues). The probability of a duplicate is negligible (one in 2^122).
Are generated UUIDs uploaded or sent to a server?
No. All UUIDs are assembled locally in your browser tab. No network calls or database logs are created.
What output formats are supported?
You can generate UUIDs in standard lowercase hyphenated notation (8-4-4-4-12), uppercase, compact 32-character hexadecimal without hyphens, surrounded by braces ({uuid}), or as a Uniform Resource Name (urn:uuid:...).
Can I bulk generate UUIDs and export them?
Yes. You can select quantities from 1 to 100 UUIDs, copy the entire list with one click, or download the batch as a plain text (.txt) file.
How do I generate a UUID v4 programmatically?
Use the native crypto.randomUUID() method available in all modern browsers and Node.js. If implementing manually, generate 16 random bytes, set byte[6] = (byte[6] & 0x0f) | 0x40 (version 4) and byte[8] = (byte[8] & 0x3f) | 0x80 (RFC 4122 variant), and format as 8-4-4-4-12 hex.