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TinySolve

UUID Generator

Generate UUIDs in bulk — version 4 for randomness, version 7 when they need to sort.

Runs in your browser — nothing you type is sent anywhere

Version

Version 4 is 122 random bits. Use it when an identifier only needs to be unique.

About the UUID Generator

A UUID is a 128-bit identifier long enough that two systems can generate them independently and never collide in practice. That property is what makes them useful: you can create a record's identifier on a phone that is offline and be confident it will not clash with one created on a server at the same moment.

Version 4 is almost all random — 122 bits of it — and is what most people mean by a UUID. Version 7 is newer and puts the creation time in the first 48 bits, followed by random bits. That single change makes them sort in the order they were created, which matters more than it sounds if they are going into a database as primary keys: random keys scatter inserts all over the index, while time-ordered keys append to the end of it.

Both are generated using your browser's cryptographic random source, not the ordinary random function. That distinction is real — a predictable identifier can be guessed, and identifiers routinely end up in URLs where guessing one means reaching someone else's record.

You can generate up to a hundred at once, copy any single one, or copy the whole set as a list. Nothing is generated on a server, which also means no two people are ever handed the same batch.

How to use the UUID Generator

  1. Choose the version

    Version 4 for a purely random identifier, or version 7 when they will be stored in a database and should sort by creation time.

  2. Choose how many

    From one to a hundred at a time. A new set is generated whenever you change the version or the count.

  3. Generate more if you need to

    The New set button produces a fresh batch. Every one is independent, so there is no cost to discarding a set.

  4. Copy what you need

    Copy a single identifier from its row, or copy the whole list at once for pasting into a file or a query.

Frequently asked questions

What is the difference between UUID v4 and v7?
Version 4 is essentially all random. Version 7 begins with the creation time in milliseconds and fills the rest with random bits, so identifiers sort chronologically. Use v4 when you only need uniqueness, and v7 when they will be database keys or need ordering.
Why does v7 matter for databases?
Because random keys scatter inserts across the whole of a B-tree index, which fragments it and slows writes as the table grows. Time-ordered keys append to the end of the index instead, which is far cheaper and keeps recent rows physically close together.
Can two UUIDs ever be the same?
In theory yes, in practice no. Version 4 has 122 random bits, so you would need to generate billions a second for many years before a collision became likely. That is why they can be created independently on different machines without any coordination.
Are these safe to use as security tokens?
They are generated from a cryptographic random source, so a v4 UUID is unguessable. Even so, prefer a purpose-made token for authentication: UUIDs often end up in logs and URLs, where a credential should not be.
Are they generated on a server?
No, they are created in your browser. That means nothing is transmitted, and it also means no two visitors can ever receive the same batch by accident.

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