RandTools

UUID Generator

Generate UUID v4 values instantly for development, testing, and database keys

BatchFreeBrowser-only

Generates UUID v4 values with crypto.randomUUID(). RFC reference

Click Generate to get started!

Press Enter to generate

About this tool

What is a uuid generator?

A UUID generator is a free online tool that creates UUID v4 identifiers in the standard 8-4-4-4-12 format using secure random values. It is commonly used by developers to create database keys, request IDs, mock data, session tokens, and test fixtures that need to stay unique across apps, environments, and distributed systems without manual coordination.

How it works.

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Generate Instantly
The page creates one UUID v4 as soon as it loads, so there is always a value ready to copy without an extra click.
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Choose Batch Size
Switch between 1, 10, 50, or 100 results depending on whether you need a single ID or a full set of fixtures for development and QA.
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Copy and Use
Copy one UUID or the full batch and drop the values into database seeds, API payloads, session tests, or distributed tracing workflows.

When you'd use this.

Database Keys in Distributed Systems

Teams often choose UUID v4 values over auto-incrementing integers when records can be created in multiple services, workers, or regions at the same time. Random UUIDs remove the need for central coordination and are easy to generate anywhere in the stack.

Mock Data and Seed Files

QA engineers and backend developers frequently need dozens of realistic IDs for fixtures, test payloads, and migration rehearsals. Batch generation makes it easy to copy 50 or 100 UUIDs into JSON, SQL, or API clients in a single step.

Request Tracing and Session Workflows

UUID v4 values are also useful for request IDs, correlation IDs, and temporary session identifiers in logs and integration tests. The format is recognizable, safe to paste into tooling, and convenient for debugging across multiple systems.

About UUID Generator.

Generate UUID v4 values instantly with a browser-native cryptographic API instead of a hand-rolled algorithm. This UUID generator uses `crypto.randomUUID()` to create 128-bit identifiers that match the familiar 8-4-4-4-12 format developers expect for primary keys, mock API payloads, background jobs, session tracking, and distributed-system records. It is especially useful when you need one identifier immediately on page load, or when you need 10, 50, or 100 UUIDs in a batch for fixtures, seed scripts, and QA datasets. Because generation happens locally in the browser, there is no network request, no signup, and no delay. The page also explains that these are version 4 UUIDs generated from secure random bytes, making the output practical for day-to-day engineering tasks where fast copy-and-paste matters as much as standards compliance.

Frequently asked.

What version of UUID does this tool generate?+
This page generates UUID v4 values, which means the identifier is created from secure random bytes instead of timestamps or hardware addresses. That makes it a strong default for general development and testing use.
Does this UUID generator use crypto.randomUUID()?+
Yes. In supported browsers the tool uses the built-in `crypto.randomUUID()` API, so the output comes from the platform crypto implementation rather than a custom string generator.
Why would I use UUIDs instead of auto-incrementing IDs?+
UUIDs are useful when records can be created in multiple services or environments without a shared counter. They reduce collision risk across databases, queues, and background jobs, and they are convenient for imported or merged datasets.
Can I generate a large batch for fixtures or seed data?+
Yes. You can generate 1, 10, 50, or 100 UUIDs at once, then copy the entire batch for seed scripts, mock API responses, database fixtures, or load-testing datasets.
Are UUID v4 values suitable for secrets or auth tokens?+
They are fine for many identifiers such as request IDs and session references, but dedicated token formats are still better when you need revocation rules, embedded metadata, or longer secret material for authentication.