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UUID Generator

Use this UUID generator to create random identifiers for database rows, fixtures, logs, config files, prototypes, and test records without sending values to a server.

Live generator

UUID generator

UUID v4
Generated0 UUIDs
Hyphenated. Lowercase.
First UUID checkInvalid
Variant: Invalid.
UUID summary
Quick generation summary for IDs, fixtures, test records, database rows, and configuration snippets.
MeasureValue
UUID versionUUID v4
Count0
FormatHyphenated
CasingLowercase
VariantInvalid
Generation note
UUID v4 values are random identifiers, not secrets. They are useful for record IDs and test data, but do not use them as passwords, access tokens, or authorization checks.
Generation method
UUID v4 generation method
UUID v4 = 16 random bytes with version bits set to 0100 and RFC variant bits set to 10
UUIDs are identifiers, not secrets. Do not use generated UUIDs as passwords, API keys, or authorization tokens.
How to use
Steps
  1. Choose how many UUIDs to generate.
  2. Select lowercase or uppercase output.
  3. Choose plain, braced, or URN formatting.
  4. Turn hyphens on or off, then copy the generated list.
Example
Sample output
VersionUUID v4
Shapexxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
URN optionurn:uuid:...
Generator use
Best for
  • Browser-side link, file, format, and web utility tasks that need an output now.
  • Generating reusable artifacts such as QR codes, snippets, exports, or cleaned payloads.
Before relying on it
Check first
  • UUIDs are identifiers, not secrets. Do not use generated UUIDs as passwords, API keys, or authorization tokens.
  • Publishing a generated file or code without testing it in the real destination.
  • Encoding private or sensitive data into an output that other people can scan, copy, or inspect.
Details
What to know before using the output
Version bits4
The generator sets the UUID version nibble to 4 after creating random bytes.
Variant bitsRFC 4122 / RFC 9562
The variant bits are set to the standard 10 pattern used by modern UUIDs.
Security boundaryIdentifier only
UUID v4 collision risk is low for normal ID use, but UUIDs are visible identifiers and should not grant access by themselves.
Source notes
References used for this generator
RFC 9562Defines UUID formats, variants, and the UUID version 4 random generation layout.MDN Web DocsDocuments browser support for crypto.randomUUID and secure random UUID generation.
Benchmarks
How to read the output
Hyphenated UUID: 36 chars. 
The common display format includes four hyphens.
Compact UUID: 32 hex chars. 
Some APIs and storage formats accept UUIDs without hyphens.
URN UUID: urn:uuid:. 
URN form is useful when a standards-oriented identifier string is expected.
Method and limitations
Methodology and assumptions
Formula, inputs, limitations and review record
Generation method
UUID v4 = 16 random bytes with version bits set to 0100 and RFC variant bits set to 10
Inputs used
How many, Casing, Wrapper, Hyphen option
Limitations
Utility outputs depend on the encoded payload, file format, target app, scanner, printer, browser, and real-world testing before sharing.
Review record
Catalog QA baseline on June 6, 2026. This date marks the catalog-wide automated and editorial QA baseline, not a tool-specific expert review.
Cite this page
Toolkit Shelf. UUID Generator. https://toolkitshelf.com/tools/uuid-generator
FAQ
Common questions
Is a UUID the same as a GUID?
In most practical software contexts, GUID and UUID refer to the same 128-bit identifier format, though wording differs by platform.
Are UUID v4 values secret?
No. UUIDs are identifiers. Do not use them as passwords, API keys, reset tokens, or authorization decisions.
Why does UUID v4 always include a 4?
The 4 marks the UUID version. UUID v4 uses random bytes with specific version and variant bits set.