Free UUID Generator Online
Generate one or many cryptographically random UUIDs (v4) instantly — in bulk, in your browser, with zero server calls.
How it works
Set quantity
Choose how many UUIDs to generate — from 1 up to 100 at once.
Choose format
Standard hyphenated UUID, or uppercase, or no hyphens.
Generate
Click Generate or press Enter to get cryptographically random UUIDs.
Copy or download
Copy all UUIDs to clipboard or download as a .txt file.
Common use cases
Database primary keys
Use UUID v4 as primary keys in distributed databases to avoid ID collisions across nodes — no central sequence needed.
Test data generation
Generate dozens of unique IDs at once to seed a test database, mock API, or fixture file.
File naming
Give uploaded files UUID-based names to avoid collisions and prevent guessing — a common pattern in object storage (S3, GCS).
Session and token IDs
Use UUIDs as the basis for session tokens, API keys, or CSRF tokens where global uniqueness matters.
Frequently asked questions
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit label formatted as 8-4-4-4-12 hex characters. UUID v4 is randomly generated and has a collision probability so low it's considered practically impossible.
Is UUID v4 truly random?
UUID v4 uses 122 random bits. This tool uses crypto.randomUUID() which draws from the browser's CSPRNG (cryptographically secure pseudorandom number generator).
How likely is a UUID collision?
Generating 1 billion UUIDs per second for 100 years gives a 50% chance of a single collision. For practical purposes, collisions are impossible.
What is the difference between UUID v1 and v4?
UUID v1 is based on the current timestamp and MAC address (not random). UUID v4 is purely random. v4 is preferred when you don't need time-ordering.
Does my generated UUID leave my browser?
No. crypto.randomUUID() is a native browser API. The UUIDs are generated entirely client-side.
Can I use these UUIDs in production?
Yes — crypto.randomUUID() meets production-quality randomness requirements and is supported in all modern browsers.