What is a random UUID generator?
A random UUID generator creates version 4 Universally Unique Identifiers using secure random data. A UUID is a 128-bit identifier that different systems can generate independently without coordinating a central sequence. This tool generates UUID v4 values for identifiers, test data, database records, API resources, and similar development tasks. It does not generate time-ordered, name-based, or Microsoft-specific GUID formats.
UUID v4 reserves six bits for its version and variant and uses the other 122 bits for random data. The tool uses the browser’s Web Crypto API and processes every result locally.
How to generate UUID v4 values
- Set Quantity from 1 to 100.
- Open Options to use uppercase characters or remove hyphens.
- Select Generate.
- Copy the complete result, or download multiple UUIDs as a TXT file.
Selecting Generate again replaces the current batch. Format changes update the current results without generating new UUIDs.
UUID v4 format
A standard UUID contains 32 hexadecimal characters and four hyphens in an 8-4-4-4-12 pattern:
a987fbc9-4bed-4078-8f07-9141ba07c9f3The standard text form is 36 characters long. Removing the hyphens produces a compact 32-character value. In a UUID v4, the first character of the third group is 4; the first character of the fourth group is 8, 9, a, or b, which identifies the standard UUID variant.
Common UUID v4 uses
- Database record and API resource IDs.
- Fixtures, seed data, and mock API responses.
- Request, log, message, and background-job correlation IDs.
- File, asset, and distributed-object identifiers.
A UUID identifies an object. Do not treat a UUID as a password, API key, access token, or other secret.
UUID v4 vs UUID v7
| Feature | UUID v4 | UUID v7 |
|---|---|---|
| Main data | Random data | Timestamp and random data |
| Ordering | Not time ordered | Time ordered |
| Common use | General IDs, tests, API resources | Time-oriented database records |
| This tool | Supported | Not supported |
Use UUID v4 when you need a general random identifier. UUID v7 is a separate task for systems that benefit from chronological sorting or improved database write locality.
UUID vs GUID
UUID and GUID commonly describe the same kind of 128-bit identifier. UUID is the standards-based term, while GUID is common in Microsoft, Windows, and .NET environments. GUID tools may add braces, C# syntax, or other Microsoft-specific output. This tool stays focused on UUID v4 with case and hyphen formatting only.
UUID generator FAQ
What is a UUID v4?
UUID v4 is the random-data version of the UUID standard. Correctly generated values include fixed version and variant bits plus 122 random bits.
How many characters are in a UUID?
The standard text form has 36 characters: 32 hexadecimal characters and four hyphens. Without hyphens, it has 32 characters.
Can two UUID v4 values be the same?
Yes, a collision is theoretically possible. With a secure random source and 122 random bits, the probability is extremely low, but UUIDs should not be described as absolutely guaranteed to be unique.
Can a random UUID be decoded?
A UUID v4 does not encode a name, original value, or recoverable timestamp. Its text reveals the UUID format, version, and variant, not the data that led to it.
Can UUID v4 be a database primary key?
Yes. Prefer a database’s native UUID type or a 16-byte representation when available. Random UUID v4 values are not ordered by creation time, which can matter for some indexes and write patterns.
Should I use a UUID as a password or API key?
No. UUIDs are identifiers, not authentication secrets. Use a purpose-built secure token with the required entropy and access controls.