UUID Generator
Generate one or many RFC-compliant UUIDs — v4 (random) by default, with v1 and v7 options — in the exact casing, hyphen, and brace format you need. It all runs in your browser, so no identifier ever leaves your machine.
What is the UUID Generator?
This UUID generator creates universally unique identifiers — 128-bit
values, written as 36-character strings like
f47ac10b-58cc-4372-a567-0e02b2c3d479, that are unique enough
to be used as keys without any central server handing them out. It produces
version 4 (random) UUIDs by default and can also create version 1
(time-based) and version 7 (time-ordered) identifiers, in single or bulk
quantities, with the exact casing and formatting your code expects.
Everything runs in your browser, so no identifier is ever sent to a server.
How to use it
- Pick a version, set how many you need, choose the casing and hyphen and brace options, then click generate.
- Choose the format: uppercase or lowercase, with or without the four hyphens, and with or without
{curly braces}(the style .NET and SQL Server like for GUIDs). - For a batch, set the quantity and the tool generates the whole list at once.
- Click Copy all to grab the entire batch, then paste it straight into your code, database, or config file.
It is a one-screen tool: generate, copy, and you are gone.
The method behind it
A UUID is 128 bits laid out in five hyphen-separated groups (8-4-4-4-12 hex characters), with a version digit and a variant marker baked into fixed positions.
- Version 4 fills the remaining 122 bits with random data.
This tool uses the browser's built-in
crypto.randomUUID(), which draws from a cryptographically secure random source — the same kind of randomness used for security tokens. - Version 1 encodes a 60-bit timestamp (100-nanosecond intervals since 1582) plus a clock sequence and a node identifier, which was historically the network card's MAC address. It is time-based but can reveal when and roughly where it was made.
- Version 7 also embeds a timestamp — Unix time in milliseconds — but puts it at the front of the value, so v7 UUIDs naturally sort in creation order while the rest of the bits stay random.
The version digit (the first character of the third group) tells any system reading the UUID which scheme produced it.
Examples
- Random key, lowercase, default format (v4):
9b2f18d4-6c7a-4f3e-8a21-d5e0c1b4a6f0 - GUID style for .NET / SQL Server (v4, uppercase, braces):
{3F2504E0-4F89-41D3-9A0C-0305E82C3301} - No-hyphen token (v4, lowercase):
a1b2c3d4e5f607189a0bccddeeff0011 - Time-ordered primary key (v7):
018fd3c2-7a91-7e44-b3c0-9f12ab34cd56— note the leading characters increase over time, so rows insert in order.
Common use cases
- Database primary keys — unique IDs you can mint on the application side without a sequence or
AUTO_INCREMENT, which matters when several services write to the same table. - Distributed and event IDs — message IDs, request/trace IDs, and event keys across microservices that must not collide even though no shared counter exists.
- Test data and fixtures — seed a column or a JSON file with a batch of realistic-looking IDs in one click.
- Idempotency and correlation keys — attach a UUID to an API call so retries are de-duplicated.
- GUIDs in Microsoft stacks — COM, .NET, and SQL Server identifiers, where v7 is increasingly preferred for index-friendly keys.
Why use this one
Most online UUID tools only spit out a single v4 value. This one does
v4, v1, and v7 in the same place, generates
batches with one-click copy-all, and gives you
format controls (case, hyphens, braces) so the output
drops directly into SQL, C#, JSON, or an env file with no hand-editing. It
uses the browser's secure crypto.randomUUID(), needs no
account, and never sends an identifier to a server. It sits alongside a few
related generators: the Password Generator
for secure passwords, the Random Number
Generator for numeric picks, and the Tokenizer
for inspecting how text breaks into tokens.
Frequently asked questions
What is the difference between UUID v4, v1, and v7?
UUID v4 is generated from random data and is the safe default when you just need a unique value with no ordering. UUID v1 encodes a timestamp plus a node identifier (historically the machine's MAC address), so it is time-based but can leak host information. UUID v7 also embeds a Unix-millisecond timestamp but places it at the front so the IDs sort in roughly creation order — which makes them friendlier as database primary keys because new rows are inserted near the end of an index instead of scattered randomly.
Are UUIDs really guaranteed to be unique?
They are not guaranteed in an absolute sense, but the collision probability is so small it is treated as zero in practice. A version 4 UUID has 122 random bits. You would need to generate on the order of a billion UUIDs per second for about 85 years to have a 50% chance of a single collision, which is why UUIDs are used as keys without a central authority handing them out.
Is a GUID the same thing as a UUID?
Yes. GUID (Globally Unique Identifier) is Microsoft's name for the same 128-bit value defined by the UUID standard. They are interchangeable; .NET, SQL Server, and Windows just call them GUIDs and often display them in uppercase wrapped in curly braces. This tool's casing and brace toggles let you produce either style.
Is this UUID generator safe to use for production identifiers?
Yes for v4. The default v4 output uses the browser's crypto.randomUUID(), which draws from a cryptographically secure random source, so the values are suitable for primary keys, request IDs, and tokens. Nothing is sent to a server — every UUID is generated locally in your browser — so it is also safe to use behind a firewall or offline.
Can I generate many UUIDs at once?
Yes. Set the quantity, pick a version and format, and the tool produces the whole batch instantly. Use the copy-all button to grab every ID at once, which is handy for seeding a database, building test fixtures, or pasting a column of values.