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Crypto-Secure

Free Online UUID Generator

Generate universally unique identifiers (UUIDs) instantly using the Web Crypto API. Each UUID v4 is a 128-bit random identifier formatted as a 36-character string, guaranteed to be virtually collision-free across all systems.

Need multiple identifiers at once? Generate up to 100 UUIDs in a single click. Your data never leaves your browser — ideal for database keys, API tokens, test fixtures, and distributed system identifiers.

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Generated locally using your browser's Web Crypto API. No data is transmitted.
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How It Works (Step-by-Step)

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1. Choose Quantity

Select how many UUIDs you need — from a single identifier to a batch of 100.

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2. Generate Instantly

Click Generate to create cryptographically random UUID v4 values using your browser's built-in Web Crypto API.

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3. Copy and Use

Copy individual UUIDs or the entire batch to your clipboard for immediate use in code, databases, or configuration files.

Key Features & Advantages

Cryptographic Randomness

Uses crypto.randomUUID() backed by the Web Crypto API instead of Math.random(), ensuring each UUID meets RFC 4122 standards for unpredictability.

Bulk Generation

Generate up to 100 unique identifiers at once — perfect for seeding databases, writing test fixtures, or provisioning distributed systems.

Flexible Formatting

Toggle between standard hyphenated format (550e8400-e29b-41d4-a716-446655440000) and compact format without hyphens. Switch between lowercase and uppercase output.

Completely Private

All UUID generation runs locally in your browser using native cryptographic APIs. No identifiers are transmitted, stored, or logged anywhere.

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Frequently Asked Questions

What is a UUID?
A Universally Unique Identifier (UUID) is a 128-bit label used to uniquely identify information in computer systems. UUID v4 uses random or pseudo-random numbers, making each value virtually guaranteed to be unique without central coordination.
What is UUID v4?
UUID version 4 generates identifiers using random numbers. The version digit (the 13th hex digit) is always "4", and one other nibble indicates the variant. All remaining 122 bits are randomly generated, providing approximately 5.3 × 10^36 possible values.
What is the difference between a UUID and a GUID?
UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) refer to the same concept. UUID is the standard term defined by RFC 4122, while GUID is the term commonly used in Microsoft ecosystems. They are functionally identical.
Is generating UUIDs in the browser secure?
Yes. This tool uses the Web Crypto API (crypto.randomUUID or crypto.getRandomValues), which provides cryptographically strong random values. This is the same source of randomness used by TLS and other security protocols in your browser.
Can two UUIDs ever be the same?
While theoretically possible, the probability of generating duplicate UUID v4 values is astronomically low — roughly 1 in 2^122 (about 5.3 × 10^36). You would need to generate approximately 2.7 quintillion UUIDs to have a 50% chance of a single collision.
Can I generate multiple UUIDs at once?
Yes. Use the quantity slider to generate anywhere from 1 to 100 UUIDs in a single batch. All values are generated instantaneously using your browser's cryptographic random number generator.

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