๐UUID Generator
A UUID (Universally Unique Identifier) is a 128-bit identifier that is globally unique. Also known as GUID (Globally Unique Identifier), UUIDs are used whenever a collision-free unique value is needed โ database primary keys, distributed system object identification, session IDs, filenames, and more. UUID v4 is generated using cryptographically secure random numbers, with a collision probability so low (1 in 2^122) that it's practically unique. This tool generates multiple UUID v4 values at once in various formats.
How to Use
- 1Set Count
Specify how many UUIDs you want to generate at once. You can generate from 1 to many in bulk.
- 2Choose Format
Select your preferred format: standard (lowercase with hyphens), uppercase, no dashes, or braced.
- 3Generate & Copy
Click 'Generate' to create UUIDs. Copy individual values or use 'Copy All' for batch copying.
Tips
- ๐กUses the Crypto API for cryptographically secure UUID generation.
- ๐กUsing UUIDs as database primary keys enables unique ID generation without server synchronization โ ideal for distributed systems.
- ๐กThe no-dash format is convenient for use in URLs or filenames.
- ๐กThe braced format is commonly used in Microsoft technology stacks (C#, .NET).
FAQ
- Q. What is the difference between UUID v4 and v7?
- A. UUID v4 is entirely random, while UUID v7 embeds a millisecond-precision timestamp making it sortable by creation time. v7 is preferred for database primary keys because it reduces index fragmentation.
- Q. What is the probability of a UUID collision?
- A. UUID v4 uses 122 bits of randomness. The probability of generating two identical UUIDs is astronomically small โ you would need to generate billions of UUIDs per second for millions of years to have a 50% chance of a collision.
- Q. What are the trade-offs of using UUID as a database primary key?
- A. Pros: IDs can be generated client-side without a database round-trip, and records from different databases can be merged safely. Cons: v4 UUIDs are random and cause B-tree index fragmentation. Use v7 to keep IDs roughly sorted.