UUID Generator

Generate 1 to 1,000 random UUID v4 values with the Web Crypto API. Lowercase or uppercase, hyphens, braces or no hyphens; copy or download TXT/CSV.

Developer Runs client-side Free to use

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About the UUID Generator

UUID Generator creates random version 4 UUIDs — 128-bit identifiers such as 3f2b8c1e-9d4a-4f6b-8e2c-1a7d5b9c0e3f — in batches of 1 to 1,000. Values come from your browser’s Web Crypto API: crypto.randomUUID() when available, otherwise an RFC-compliant version built from crypto.getRandomValues(). Math.random() is never used.

Format the list as lowercase or uppercase, with standard hyphens, wrapped in braces, or as 32 characters with no hyphens, then copy single values, copy everything, or download a .txt or .csv file. This tool generates version 4 UUIDs only.

How to use

Enter how many UUIDs you need, from 1 to 1,000.
Choose lowercase or uppercase and a format: standard, braces or no hyphens.
Click Generate UUID v4.
Copy a single value with its copy button, or use Copy All.
Download the list as .txt (one per line) or .csv (with a uuid header).

Key features

Cryptographically secure randomness from the Web Crypto API.
Correct version (4) and RFC variant bits in every value.
Batch sizes from 1 to 1,000.
Lowercase or uppercase, hyphenated, braces or hyphen-free output.
Individual copy buttons, Copy All, and TXT/CSV downloads.
Changing the format reformats the same values instead of generating new ones.

Best practices

Store UUIDs in a native UUID column type where your database supports one.
Use lowercase standard format unless a system requires otherwise — RFC 9562 output is lowercase.
Don’t treat UUIDs as secrets or passwords; they identify things, they don’t authorise access.
If you need sortable time-based IDs, use a library that generates UUID v7; this tool makes v4 only.
Generate test data in batches and keep the CSV with your fixtures for repeatable tests.

Benefits

Instant unique IDs for databases, APIs, test fixtures and filenames.
No sign-up, rate limit or server round trip.
Values never leave your browser.
Bulk output saves writing a one-off script.

Frequently asked questions

What is a UUID v4?

A 128-bit universally unique identifier where 122 bits are random. The version digit is 4 and the variant bits mark it as an RFC 9562 (formerly RFC 4122) UUID.

Are these UUIDs secure and random?

Yes. They use the browser’s Web Crypto API (crypto.randomUUID or crypto.getRandomValues), which is designed for cryptographic randomness. Math.random is never used.

Can two generated UUIDs collide?

In practice, no — with 122 random bits a collision is so unlikely that it can be ignored for normal applications.

Does this tool generate v1, v5 or v7 UUIDs?

No. It generates version 4 UUIDs only.

Is a GUID the same as a UUID?

GUID is Microsoft’s name for the same 128-bit identifier format. The braces format is the style commonly used for GUIDs.

Are the UUIDs sent anywhere?

No. They are generated and kept in your browser until you copy or download them, and Reset clears them.