UUID Generator

Produce identifiers in the standard 8-4-4-12 hexadecimal shape, one at a time or up to five hundred at once, with dashed, dashless and uppercase output formats.

What is the UUID Generator?

A UUID is a 128-bit value written as 32 hexadecimal digits in five dash-separated groups of eight, four, four, four and twelve. This page builds them from Math.random and stamps the version digit into the thirteenth hex position: a 4 for the random variety, or a 1 if you switch to the time-based button. The single-UUID card and the bulk list both follow whichever format radio is selected.

Key Features

• Version 4 random UUIDs in the familiar RFC 4122 layout
• Version 1 button for anything that expects a 1 there
• Three output formats: dashed, dashless thirty-two characters, or uppercase
• Bulk generation of up to five hundred identifiers per press
• Download the batch as uuids.txt, one identifier per line

Common Use Cases

• Assigning primary keys before a row ever reaches the database
• Creating correlation IDs to trace one request across several services
• Filling a test fixture with five hundred distinct record identifiers
• Naming uploaded files so two users cannot overwrite each other

How to Use the UUID Generator

1. Leave Version 4 (Random) selected unless something downstream specifically wants the version 1 shape.
2. Choose With dashes, No dashes or Uppercase; the radios are exclusive, so uppercase keeps its dashes.
3. Press Generate New UUID for a single value, then Copy to take it.
4. For a batch, set Number of UUIDs up to 500 and press Generate in the Bulk card.
5. Use Download for a uuids.txt file, or Clear to empty the list before starting again.

Tips for Best Results

• Stick to version 4 here, since the version 1 output carries no MAC address, clock sequence or readable timestamp.
• Store them in a binary or native UUID column rather than a 36-character string where your database allows it.
• Uppercase and dashless forms describe the same value, so normalize on one before comparing them.
• Treat these as identifiers, never as secrets - a UUID should not stand in for a token.

Why Use WiserWork's UUID Generator?

Sequential integer keys have to come from a single authority, which means a round trip before you can name a record, and they leak volume: order 1042 tells a competitor how many orders you have taken. A UUID can be minted anywhere, offline, on the client, or in two services at once, and the results still merge cleanly. Do note that these particular values come from Math.random rather than crypto.getRandomValues, so they are fine as identifiers and wrong as unguessable tokens.

Who Uses the UUID Generator?

Backend and mobile developers generating keys ahead of a sync, QA engineers who need bulk fixture data, and integration teams tagging messages with a correlation ID. Anyone debugging a distributed trace ends up reading these strings all day.

Frequently Asked Questions

Which UUID version does this produce?

Version 4 by default, with a version 1 option. Both are assembled from Math.random in the page, and the version digit is written into the thirteenth hex position, so v4 strings show a 4 there and v1 strings show a 1.

Is the version 1 output a real time-based UUID?

Not to spec. RFC 4122 version 1 encodes a 60-bit timestamp, a clock sequence and a node identifier taken from the network card. This one folds the current millisecond into random digits in a way that leaves no recoverable date, so prefer version 4 unless something merely validates the shape.

What does 8-4-4-12 refer to?

The count of hexadecimal digits in each dash-separated group. Thirty-two digits plus four dashes make the canonical 36-character string; removing the dashes expresses the same 128-bit value in 32 characters.

Could two UUIDs ever collide?

A version 4 UUID leaves 122 bits free, about 5.3 undecillion possibilities. Generating a billion of them every second for roughly eighty-five years would give you an even chance of one duplicate, which is why applications mint them without coordinating.

Why use a UUID instead of an auto-incrementing integer?

Because you can create one before touching the database, on a phone that is offline, or in two services whose data later merges without renumbering. Sequential IDs also disclose record counts and invite anyone to walk your URLs one number at a time.

Are these safe to use as security tokens?

No. They come from Math.random, a predictable pseudorandom generator rather than a cryptographic one, so the collision math above assumes better randomness than you are actually getting. For reset links, session IDs or API keys, use crypto.getRandomValues on the server.

What is the maximum batch size?

Five hundred per press. The counter above the list shows how many are currently held, and pressing Generate again replaces the batch rather than adding to it.

Does the tool remove duplicates inside a batch?

It does not check. Each value is drawn independently, and at 122 bits of width a repeat inside five hundred draws is not a realistic concern.

Can I get uppercase without dashes?

Not in one step, because the three format options are radio buttons and only one applies at a time. Copy the dashless form and uppercase it in your editor when you need both.

Where do the generated UUIDs go?

Nowhere. They are created inside the page, the download is assembled from a blob in your browser, and closing the tab discards the list. Nothing reaches a server.

A UUID buys you the right to name something without asking anyone's permission first, which is why they show up as keys, trace IDs and file names. Take a batch, stay on version 4, and keep them out of your security layer.