UUID Generator Online — Random UUID v4 Generator Free
Generate random UUIDs (v4) in your browser using a cryptographically secure source. Produce a single UUID for a quick test, or generate hundreds at once for seeding fixtures, database records, and load tests. The tool runs locally — useful when you need unique IDs without depending on a backend service.
Features
Cryptographically secure
UUIDs come from `crypto.randomUUID()` or `crypto.getRandomValues` — the same source TLS uses.
Bulk generation
Generate 1, 10, 100, or any custom count in one click. Copy or download as text.
Format options
Switch between standard dashed (`xxxxxxxx-xxxx-...`), no-dash, uppercase, and braces format.
Validate UUIDs
Paste a UUID to check its version and validity.
How to generate a UUID online
Produce one or many UUIDs in seconds.
- Set the quantityEnter how many UUIDs you need — 1 for a quick paste, hundreds for bulk seeding.
- Pick a formatStandard lowercase with dashes is the default; toggle uppercase or remove dashes if your database prefers it.
- GenerateClick Generate to produce the requested UUIDs. The result appears immediately.
- Copy or downloadUse Copy for a single value, or Download to grab a text file of all generated IDs.
Examples
A single UUID v4
Input
count=1, format=standard
Output
f47ac10b-58cc-4372-a567-0e02b2c3d479
Frequently Asked Questions
- What is a UUID v4?
- A UUID v4 is a 128-bit identifier generated mostly from random bits. The version field is `4` and the variant bits are fixed — the rest is randomness. The probability of two v4 UUIDs colliding is astronomically small.
- How is UUID v4 different from v1?
- UUID v1 embeds a timestamp and the MAC address of the machine that generated it — predictable and potentially privacy-leaking. UUID v4 is purely random, which is what most modern applications use.
- Are the generated UUIDs unique enough to use in a database?
- Yes. The number of v4 UUIDs you would need to generate before a collision becomes likely is in the trillions. For practical purposes, they are unique.
- Is this random source good enough for security?
- Yes. The tool uses the browser's cryptographically secure random generator, the same source used for TLS keys and session tokens.
- Can I generate UUID v5 or v7?
- Today the tool focuses on v4. UUID v5 (namespace-based) and v7 (timestamp-ordered) are on the roadmap.