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Free UUID v4 generator for APIs, databases and test data

Generate UUID v4 identifiers for databases, APIs, fixtures and distributed systems.

  • 1–100 UUID v4 values
  • Hyphenated or compact
  • Uppercase option
  • Generated locally

Your tool

UUID Generator

Good to know

A UUID is a 128-bit identifier used to create unique references across databases, APIs, logs, events and distributed systems.

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Understand

Understand UUID Generator

What is UUID Generator?

A UUID is a 128-bit identifier used to create unique references across databases, APIs, logs, events and distributed systems.

Main use case: Generate one or many UUID v4 values for test data, database rows, API payloads, fixtures or technical identifiers.

Common use cases

API fixtures
Create stable IDs for sample users, orders, payments or events.
Database testing
Fill records with unique identifiers without relying on production data.
Distributed systems
Prepare identifiers that do not require a central sequence.

How to use the tool

  1. Choose how many UUIDs to generate.
  2. Enable uppercase or compact output if needed.
  3. Generate the values.
  4. Copy the result into your fixture, script or payload.

Best practices

  • Use realistic test values when validating forms, exports or API payloads.
  • Keep real customer, banking and production secrets out of public tools.
  • Check the output format before copying it into a production workflow.
  • Document whether a value is generated, validated, converted or only estimated.

Common mistakes

Confusing valid format with real-world validity
A generated or locally validated value can match a format without proving that it exists in an official system.
Using real production data
Public utilities are best for test data, demos, fixtures, QA and quick checks, not for confidential values.

FAQ

Frequently asked questions

What is a UUID v4?

A UUID v4 is a randomly generated 128-bit identifier commonly used as a unique key in software systems.

Is a UUID the same as a GUID?

GUID is Microsoft’s common name for the same type of identifier. In most web and database workflows, UUID and GUID refer to equivalent values.

Can two UUIDs be identical?

A collision is theoretically possible but extremely unlikely when UUID v4 values are generated correctly.

Should UUIDs be uppercase or lowercase?

Both forms are normally accepted. Lowercase with hyphens is the most common representation in APIs and databases.

Are my inputs sent to a server?

OnSubmit tools run in the browser whenever the task can be processed locally. Avoid pasting production secrets, real banking details or personal data into public tools.