UUID Generator
Generate random UUIDs (version 4) for unique identifiers in databases, APIs, or applications.
Set Number of UUIDs
Generated UUIDs
Enter a count to generate UUIDs
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What is a UUID (v4)?
A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. Version 4 UUIDs are the most common type; they are generated using random or pseudo-random numbers.
Because a UUID is extremely long and generated randomly, the probability of a duplicate (a "collision") is so incredibly small that it is considered zero for all practical purposes. This makes them ideal for primary keys in distributed databases.
When to Use UUIDs
- Distributed Systems: If you have multiple servers creating records simultaneously, they can generate UUIDs independently without needing to check a central database for the next available ID.
- Data Privacy: Unlike auto-incrementing IDs (1, 2, 3...), UUIDs don't reveal how many total users or orders your system has, making them more secure against scraping and enumeration attacks.
- Offline Syncing: Mobile apps can generate UUIDs for new records while offline and sync them to the server later without any ID conflicts.
How to Generate IDs
- Choose the number of IDs you need (from 1 to 100).
- Click "Generate UUIDs".
- The tool will instantly output a list of unique, cryptographically random version 4 identifiers.
- Copy the list and use it in your database scripts or test data.
Frequently Asked Questions (FAQ)
Is a GUID different from a UUID?
Functionally, GUID (Globally Unique Identifier) is Microsoft's name for the UUID standard. While there are some subtle historical differences in implementation, for 99% of web development use cases, they are exactly the same thing.
Can a UUID ever be duplicated?
Theoretically, yes. Practically, no. The number of possible UUIDs is 2128 (approximately 340 undecillion). To put that in perspective, if you generated 1 billion UUIDs per second for the next 100 years, the probability of a single collision would still be essentially zero.
How should I store UUIDs in my database?
Most modern databases like PostgreSQL and SQL Server have a native UUID data type. In MySQL, you can store them as a BINARY(16) for maximum performance, or as a CHAR(36) if you prefer human-readable strings at the cost of some storage space.