Database keys
They let records be created in several places at once with no risk of collision when synchronising.
UUID generator
Generate unique UUID v4 identifiers.
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What it is for
A UUID is a 128-bit identifier designed to be unique without anyone having to coordinate it. That is its point: two systems that neither know nor talk to each other can generate identifiers simultaneously with practical certainty they will not clash.
The classic alternative, a counter incrementing by one, requires a central authority handing out numbers. That works in a single database but breaks as soon as there are several servers, an application that must work offline, or a merge of data from two different systems.
Version 4, which this tool generates, is based on random numbers. The possible combinations are so many that the probability of two repeating is negligible in any real scenario.
How it works
- Click "Generate 5 UUIDs" to instantly create unique identifiers.
- Copy the one you need, or click again to generate new ones.
- Use them as unique identifiers in your databases or applications.
When to use it
Offline applications
A client working without a connection can generate valid identifiers and upload them later.
Unique file names
They stop two files uploaded at the same moment overwriting each other by sharing a name.
Practical tips
- They are generated with the browser’s cryptographic generator, not a simple random function.
- They are not secret: a UUID must never be used as though it were a password or an access token.
- As a primary key they take more space and sort worse than a sequential number. They pay off when you need independence between systems.
- They are written in lowercase by convention, although they are not case sensitive.
Frequently asked questions
Can two UUIDs from this tool ever repeat?
Practically impossible: they're generated with the UUID v4 standard, which uses random numbers with so many possible combinations that the chance of a collision is negligible.
What exactly is a UUID?
A 128-bit universally unique identifier, widely used in programming to identify records or resources without relying on a central counter.