How to use the UUID Generator
1. Enter the number of UUIDs you need in the count field (from 1 up to 1,000).
2. Click the Generate button to create a fresh batch of unique identifiers.
3. Click the copy icon next to any individual UUID to copy it to your clipboard, or use Copy All to copy the entire list as a newline-separated string.
4. Click Generate again at any time to produce a new batch — each call creates entirely new, unrelated UUIDs.
What is it?
A UUID (Universally Unique Identifier), also called a GUID (Globally Unique Identifier), is a 128-bit label standardised by RFC 4122. It is represented as a 32-character hexadecimal string divided into five groups by hyphens — for example: 550e8400-e29b-41d4-a716-446655440000. The format is ubiquitous in software engineering because it allows independent systems to create identifiers without a central coordinating authority.
This tool generates UUID version 4 — the most commonly used variant, where all 122 significant bits are randomly generated. The remaining 6 bits encode the version (4) and variant (RFC 4122). The randomness comes from the crypto.getRandomValues() Web API, which provides cryptographically secure random numbers suitable for security-sensitive identifiers. The probability of two UUIDv4s colliding is astronomically small: roughly 1 in 5.3 × 10³⁶ — far smaller than the chance of a random cosmic ray flipping a bit in your RAM.
UUIDs are widely used as database primary keys (especially in distributed systems where auto-increment integers would conflict across shards), session tokens, transaction IDs, file names for uploaded assets, and anywhere a globally unique identifier is needed without coordination.
Example
Count: 5
550e8400-e29b-41d4-a716-446655440000 a87ff679-a2f3-471d-8a70-a657b6c98a93 f47ac10b-58cc-4372-a567-0e02b2c3d479 7c9e6679-7425-40de-944b-e07fc1f90ae7 c67e0de4-a4ae-4ce2-b6d8-1aef27d1f5d3
Each UUID is version 4 (random). Generated using crypto.getRandomValues() — safe for database primary keys.
Benefits
Collision-free IDs for distributed systems without coordination
UUID v4 uses 122 bits of entropy — the probability of collision across a trillion IDs is negligible, with no central ID authority needed.
Create primary keys for database records without auto-increment
Services assign UUIDs independently — no database round-trip is needed to get the next ID before inserting a record.
Seed test databases with realistic identifier values
UUID primary keys in test fixtures mirror production data shapes — avoids test IDs that are easy to confuse with real records.
Bulk-generate UUIDs for batch imports or fixture files
Generate dozens of unique identifiers at once — ready to paste into SQL seed files, JSON fixtures, or CSV imports.
Frequently asked questions
Are these UUIDs really unique?
Yes. They are generated using the Web Crypto API (crypto.getRandomValues), which provides cryptographically strong randomness. The chance of a collision between any two UUIDv4 values is approximately 1 in 5.3 × 10³⁶ — effectively impossible in practice.
What is the difference between UUID v4 and v1?
UUID v1 is generated from your machine's MAC address and the current timestamp, which means it encodes traceable information. UUID v4 is fully random and does not leak any system information, making it the preferred choice for most modern applications.
Can I use these UUIDs as database primary keys?
Yes, UUIDv4 is commonly used as a primary key — particularly in distributed databases or microservice architectures where auto-incrementing integers from a single source would create bottlenecks. Be aware that random UUIDs cause more page splits in B-tree indexes than sequential IDs; for write-heavy databases consider UUID v7 (time-ordered) if your database supports it.
Are UUIDs case-sensitive?
No. The UUID specification treats uppercase and lowercase hex letters as equivalent. Most systems store and compare UUIDs in lowercase by convention, but both 550E8400-E29B-41D4-A716-446655440000 and 550e8400-e29b-41d4-a716-446655440000 refer to the same identifier.
Is there a rate limit or maximum on how many I can generate?
This tool allows generating up to 1,000 UUIDs per click. All generation happens in your browser — there is no server-side limit or API call. For bulk generation beyond 1,000, re-click the Generate button as many times as needed.