UUID Generator
Generate 1–100 cryptographically random UUID v4 identifiers.
UUID v4 generation tool
Generate secure random UUIDs
Choose quantity and format, generate UUIDs with Web Crypto, then copy one value or the full batch.
UUIDs are identifiers, not passwords or API keys. Use dedicated cryptographic tokens for secrets.
Primary generated UUID
Generate a UUID
Click Generate UUID to create a new random UUID v4.
Generation status
Ready
No UUID generated yet.
Primary UUID
—
Latest generated value.
UUID version
v4
Random UUID version.
Quantity generated
0
Values in the current batch.
Format
hyphenated
Hyphenated or compact output.
Case
lowercase
Lowercase or uppercase output.
Character length
36
36 with hyphens, 32 compact.
Generation method
Unavailable
Web Crypto source used.
Status
Ready
Click Generate UUID to create a new random UUID v4.
Copy current UUID
Copy the latest generated UUID for a database row, API payload, or test value.
Copy all UUIDs
Copy the full generated batch as a newline-separated list.
Privacy note
UUIDs are generated locally in your browser and should not be stored by BlinkCalc.
Accuracy note
UUID v4 is random and not sequential. For sortable IDs, consider UUID v7 or ordered IDs.
Security note
UUIDs are useful identifiers, but they are not secret tokens by default.
Browser crypto note
This generator uses Web Crypto and does not use Math.random for UUID generation.
Generated UUID list
Copy individual UUIDs or the full generated batch.
Practical UUID examples
Common places where developers use UUID v4 identifiers.
Database primary key
Use UUIDs as entity IDs when services need to create records independently.
API request ID
Attach a UUID to API requests to trace failures and logs.
Correlation ID
Use the same UUID across services to connect distributed events.
Mock data ID
Generate realistic IDs for fixtures, seeds, and tests.
React key warning
UUIDs are useful for generated data, but avoid regenerating keys on every render.
Hyphenated format
Standard UUID format uses five hexadecimal groups separated by hyphens.
Compact format
Compact UUIDs remove hyphens and use 32 hexadecimal characters.
Uppercase format
Uppercase UUIDs are usually equivalent, but lowercase is more common.
UUID v4 quick reference
UUID
Universally Unique Identifier.
UUID v4
Randomly generated UUID.
Standard length
36 characters with hyphens.
Compact length
32 characters without hyphens.
Version digit
The third group starts with 4.
Variant digit
The fourth group starts with 8, 9, a, or b.
Not sequential
UUID v4 does not sort by creation time.
Not a secret
UUIDs are identifiers, not passwords.
Web Crypto
Use secure browser crypto, not Math.random.
Developer guide
Generate UUID v4 identifiers for development workflows
UUID v4 values help developers create random identifiers without coordinating with a central counter.
What is a UUID v4 Generator?
A UUID v4 Generator creates random universally unique identifiers for databases, APIs, logs, tests, distributed systems, and development workflows.
What is a UUID?
A UUID is a 128-bit identifier commonly represented as five hexadecimal groups separated by hyphens.
What makes UUID v4 different?
UUID v4 is randomly generated. It does not encode time or machine information and is useful when multiple services need to create IDs independently.
When should developers use UUID v4?
Use UUID v4 for database IDs, API request IDs, correlation IDs, mock data, file identifiers, event IDs, public-facing non-sequential IDs, and prototypes.
UUID v4 vs sequential IDs
UUID v4 can be generated without asking a database first, but sequential IDs are shorter and may index more efficiently at large scale.
UUID v4 and security
UUIDs are identifiers, not secrets. Do not use UUIDs alone as passwords, API keys, session tokens, or authorization secrets.
How to use this UUID v4 Generator
- 1Choose how many UUIDs to generate.
- 2Select lowercase, uppercase, hyphenated, or compact format if needed.
- 3Click Generate UUID.
- 4Copy one UUID or copy the full generated list.
- 5Use the UUID in your database, API test, mock data, or development workflow.
Why developers use a UUID v4 Generator
UUID v4 Generator FAQs
It creates random UUID version 4 identifiers that can be used as unique IDs in software systems.
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