UUID Generator
Generate cryptographically random RFC 4122 version 4 UUIDs. 100% client-side — your data never leaves your browser.
Click "Generate UUIDs" to create unique identifiers
About UUID Generator
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information in computer systems. Version 4 UUIDs (the most common type) are generated using cryptographically strong random numbers, making collisions practically impossible — you would need to generate ~2.7×10^18 UUIDs to have a 50% chance of a single duplicate. This tool generates RFC 4122-compliant v4 UUIDs using the browser's native Web Crypto API (crypto.randomUUID), the same secure generator used by Node.js, PostgreSQL, and modern frameworks.
How It Works
- Choose how many UUIDs you want (1 to 100).
- Click "Generate UUIDs" — each UUID is created using crypto.randomUUID(), a cryptographically secure random generator built into your browser.
- Copy individual UUIDs or copy all at once with the "Copy All" button.
- Click Reset to clear and start over.
✨ Key Features
- ✓Generate RFC 4122-compliant version 4 UUIDs
- ✓Bulk generation — up to 100 UUIDs at once
- ✓Uses native crypto.randomUUID() — cryptographically secure
- ✓Copy individual UUIDs with one click
- ✓Copy all UUIDs as a newline-separated list
- ✓100% client-side — no data sent to any server
- ✓No signup, no limits, completely free
- ✓Fast — generates 100 UUIDs in under 1 millisecond
🎯 Common Use Cases
- →Generating primary keys for database records
- →Creating unique request IDs for API tracing
- →Seeding test data with unique identifiers
- →Generating session IDs or correlation IDs for logs
- →Creating file names that never collide
- →Distributed systems where sequential IDs are not viable
- →Frontend apps that need client-side unique IDs before server round-trip
💡 Advanced Tips & Pro Insights
- ▸crypto.randomUUID() is only available in secure contexts (HTTPS or localhost). On plain HTTP, this tool falls back to a secure polyfill using crypto.getRandomValues().
- ▸Version 4 UUIDs contain 122 random bits. Version 1 UUIDs are time-based and less private; version 7 (time-ordered) is a newer standard gaining adoption for databases.
- ▸For database primary keys, prefer UUIDv7 (time-ordered) over v4 for better index locality — but v4 is fine for most use cases.
- ▸UUIDs are case-insensitive. This tool outputs lowercase, the conventional standard.
- ▸A UUID string is always 36 characters (32 hex digits + 4 hyphens). If you see a different length, it is not a standard UUID.
Frequently Asked Questions
Is this UUID generator free to use?▾
Yes, this UUID generator is completely free with no signup, registration, or usage limits. Generate as many UUIDs as you need.
Is my data safe?▾
Yes, 100% safe. All UUIDs are generated locally in your browser using the Web Crypto API. No data is sent to any server.
What is a UUID?▾
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information in computer systems. It is typically written as 36 characters: 32 hexadecimal digits in 5 groups separated by hyphens (e.g. 550e8400-e29b-41d4-a716-446655440000).
What is the difference between UUID v1, v4, and v7?▾
UUID v1 is time-based and includes the MAC address (privacy concern). UUID v4 is fully random and the most common. UUID v7 is time-ordered random, better for database primary keys because it keeps index locality. This tool generates v4 UUIDs.
Can two UUIDs ever be the same?▾
Practically never. A v4 UUID has 122 random bits, giving ~5.3×10^36 possible values. You would need to generate ~2.7×10^18 UUIDs to have a 50% chance of a single collision — longer than the age of the universe at any realistic rate.
Are UUIDs cryptographically secure?▾
Yes, UUID v4 generated with crypto.randomUUID() uses a cryptographically secure pseudo-random number generator (CSPRNG). It is safe for security-sensitive uses like session IDs and API tokens.
Why is my UUID lowercase?▾
UUIDs are case-insensitive per RFC 4122, but lowercase is the conventional output format. Most systems accept both uppercase and lowercase.
Can I generate UUIDs in bulk?▾
Yes, this tool generates up to 100 UUIDs at once. Just set the count, click Generate, and use "Copy All" to grab them as a newline-separated list.