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UUID 生成器

Free browser tool

UUID Generator for Random UUID v4 & GUIDs

Generate random UUID v4 identifiers for database rows, request IDs, test data, and distributed systems directly in your browser.

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Quick answer

A UUID v4 generator creates random 128-bit identifiers in the standard UUID format.

Use UUIDs for identifiers and test data, not for passwords, API keys, or access tokens.

Best inputs for UUID generation

Choose the right format

Standard hyphenated UUIDs are easiest to read, while no-hyphen values fit compact systems.

Generate only what you need

Bulk output is convenient for fixtures, but production IDs should usually be generated by the application.

UUID v4 format
A UUID v4 is a random 128-bit identifier with fixed version and variant bits.

xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

The `4` marks version 4. The `y` position is one of 8, 9, A, or B in standard UUID v4 output.

Practical uses

UUIDs are useful for client-generated records, imports, fixtures, request tracing, temporary IDs, and distributed workflows where a central counter is inconvenient.

This tool is for identifiers, not passwords, secrets, API keys, or authentication tokens.

UUID method and example
UUID v4 values are random identifiers, not sequential IDs or secret tokens.

Format Assumption

xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

The version position is fixed to 4. The variant position is one of 8, 9, A, or B.

Example use

Generate 20 UUIDs for test fixtures, import rows, local draft IDs, or request correlation examples.

Limitation

UUIDs are useful identifiers, but they should not be treated as passwords, API keys, or unguessable access tokens.

Common use cases
Use UUIDs when you need independent identifiers instead of sequential counters.

Test fixtures

Generate IDs for sample rows, mock records, and local seed data.

Import rows

Create temporary identifiers for spreadsheet or CSV import examples.

Request tracing

Use UUID-shaped values in docs and debugging examples for correlation IDs.

Draft objects

Assign local IDs to prototypes, demos, and client-side examples.

Frequently asked questions

Are UUID v4 values guaranteed unique?

No random identifier can be mathematically guaranteed unique, but UUID v4 has such a large random space that collisions are extremely unlikely for normal application use.

Can I use UUIDs as database primary keys?

Yes, UUIDs are commonly used as database identifiers. Some databases also offer ordered UUID-style IDs when index locality matters.

Are UUIDs secure tokens?

No. UUIDs are identifiers, not authentication secrets. Do not use them as passwords, session tokens, or API keys.

Does this tool send generated UUIDs anywhere?

No. The generator runs locally in your browser and does not need a backend or external API.

Suggested workflow

Identifier generation path

Move from random IDs to scannable labels or fingerprints depending on how the identifier will be used.

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