UUID Generator
Generate results with the Uuid Generator — set your parameters and get cryptographically-random output instantly. Free, runs in browser, no data stored.
Formula
Output = Structured transform(Input)
This UUID Generator processes and transforms input content based on deterministic formatting/parsing rules.
Worked Examples
Example 1: Generate Database Primary Key
Problem:Create a unique ID for a new user record before inserting into database.
Solution:Generate 1 UUID: Result: f47ac10b-58cc-4372-a567-0e02b2c3d479 Use as primary key: INSERT INTO users (id, name, email) VALUES ('f47ac10b-58cc-4372-a567-0e02b2c3d479', 'John', 'john@email.com'); Benefit: ID is known before insert, enabling related records to be created simultaneously.
Result:UUID ready for database insertion
Example 2: Batch Generate for Import
Problem:Need 10 unique IDs for bulk importing products.
Solution:Set count to 10, click Generate: 1. 550e8400-e29b-41d4-a716-446655440001 2. 6ba7b810-9dad-11d1-80b4-00c04fd430c8 3. 6ba7b811-9dad-11d1-80b4-00c04fd430c8 ... (7 more) Copy all, paste into spreadsheet column, then import with your product data.
Result:10 unique UUIDs for bulk import
Example 3: API Resource Identifier
Problem:Create unique identifiers for REST API resources.
Solution:Generate UUID for each resource: Endpoint: /api/orders/9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d Advantages: - Client can generate ID before POST - No sequential pattern to guess - Safe to expose publicly - Works in distributed systems Store in database as the order's primary key.
Result:UUID-based API resource URL
Frequently Asked Questions
What is a UUID and what does it stand for?
UUID stands for Universally Unique Identifier. It's a 128-bit number used to uniquely identify information in computer systems. UUIDs are formatted as 32 hexadecimal digits displayed in 5 groups separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx (8-4-4-4-12). With 2^128 possible values (340 undecillion), the probability of generating duplicate UUIDs is astronomically low.
What is the difference between UUID and GUID?
UUID and GUID are essentially the same thing. UUID (Universally Unique Identifier) is the standard term used in most contexts and defined by RFC 4122. GUID (Globally Unique Identifier) is Microsoft's term for the same concept, used in Windows, .NET, and Microsoft documentation. Both refer to 128-bit unique identifiers with identical format and generation methods.
What are the different UUID versions?
UUID has 5 versions: v1 uses timestamp + MAC address (reveals creation time/location). v2 is DCE Security version (rarely used). v3 uses MD5 hash of namespace + name. v4 uses random/pseudo-random numbers (most common, what we generate). v5 uses SHA-1 hash of namespace + name. Version 4 is preferred for most applications due to simplicity and privacy.
How unique are UUIDs really?
Extremely unique. UUID v4 has 122 random bits, giving 5.3 × 10^36 possible values. To have a 50% chance of collision, you'd need to generate 2.7 × 10^18 UUIDs—that's 2.7 quintillion. Generating 1 billion UUIDs per second, it would take 85 years to reach 50% collision probability. For practical purposes, UUIDs are unique.
When should I use UUIDs vs auto-increment IDs?
Use UUIDs when: generating IDs on multiple servers/clients, needing IDs before database insertion, hiding record counts, or merging databases. Use auto-increment when: storage space matters (4 bytes vs 16), sequential ordering helps performance, IDs need to be human-memorable, or working with simple single-database systems. UUIDs trade storage for distribution flexibility.
Are UUIDs secure for sensitive data?
UUID v4 (random) doesn't leak information about creation time or source. However, UUIDs aren't cryptographically secure tokens—they're identifiers, not secrets. Don't use UUIDs as passwords, API keys, or session tokens. For security-sensitive applications, use cryptographically secure random generators designed for that purpose (like crypto.randomBytes).
How do I validate a UUID format?
Valid UUIDs match this pattern: 8 hex digits, hyphen, 4 hex digits, hyphen, 4 hex digits (version number first), hyphen, 4 hex digits (variant first), hyphen, 12 hex digits. Version 4 UUIDs have '4' as the first digit of the third group. The regex pattern: /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
Can I convert UUIDs to shorter formats?
Yes, but you lose the standard format. Options: Base64 encoding (22 characters), Base62 (22 chars, alphanumeric only), or custom short IDs. Some systems use 'short UUIDs' like YouTube video IDs. However, shorter formats may cause issues with systems expecting standard UUID format. Consider your use case carefully.
Do UUIDs affect database performance?
UUIDs can impact performance: they're 4x larger than 32-bit integers (16 bytes vs 4), and random UUIDs cause index fragmentation in B-tree indexes. Mitigations: use UUID v1 or v7 (time-ordered) for better indexing, store as binary(16) instead of char(36), or use integer primary keys with UUID as secondary unique column.
What is a nil/null UUID?
The nil UUID is all zeros: 00000000-0000-0000-0000-000000000000. It's defined in RFC 4122 as a special case representing 'no UUID' or 'unknown UUID.' Use it as a placeholder or default value when a UUID is required but not yet assigned. Never use nil UUID as an actual identifier in production.