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UUID v4 Generator
Generate cryptographically random UUID v4 identifiers.
uuid-gen
§01 ABOUT THIS TOOL
Overview
A UUID v4 is a 128-bit identifier where 122 bits are random, formatted as
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. This tool generates 1 to 500 of them at
once using crypto.randomUUID(), the browser’s cryptographically secure
generator — ideal for database keys, request IDs, test fixtures, and API tokens
that need uniqueness without coordination.
How to use
- Set Count (1–500) and toggle Hyphens and Uppercase as needed.
- Click Generate to produce a fresh batch — one UUID per line.
- Click Copy all to put the entire list on your clipboard.
Examples
- Default:
9b2f1c04-8a6d-4e3b-b21f-5c07d9e4a812 - Hyphens off:
9b2f1c048a6d4e3bb21f5c07d9e4a812 - Uppercase on:
9B2F1C04-8A6D-4E3B-B21F-5C07D9E4A812
Notes
Version 4 UUIDs encode no timestamp or machine information — the 4 and the
variant digit are the only fixed parts. If you need sortable, time-ordered IDs
(e.g. UUID v7 or ULID), a v4 generator is the wrong tool; use it when pure
unpredictable uniqueness is what you want.
FAQ
Are the generated UUIDs sent to or logged by a server?
No. UUIDs are produced in your browser by the built-in crypto.randomUUID() API. They never leave your machine, so no one else can see or record them.
How random are these UUIDs?
crypto.randomUUID() uses the browser's cryptographically secure random number generator. A v4 UUID carries 122 random bits, making collisions statistically negligible for any practical workload.
Can I generate UUIDs without hyphens or in uppercase?
Yes. Uncheck Hyphens to get a 32-character hex string, and check Uppercase for capital letters — useful for systems that store UUIDs in a normalized form.