How to generate UUIDs
- Choose a whole-number quantity from 1 to 100.
- Select Generate UUIDs. No source text is needed.
- Copy the complete list or download uuids.txt.
- Generate again when you need a new batch. Reset clears the displayed batch and restores the default quantity.
Each run generates new identifiers. Copying or downloading a result does not regenerate it, so you can inspect the same batch before using it.
What is a version-4 UUID?
A UUID is a 128-bit identifier commonly displayed as five groups of hexadecimal digits separated by hyphens. Version 4 uses random bits, with specific bits reserved for the UUID version and variant. It is useful when independently generated identifiers need a common format without embedding a sequence counter or a user’s name.
The displayed form contains 36 characters: 32 hexadecimal digits and four hyphens. This tool produces lowercase text in the conventional 8-4-4-4-12 grouping. It does not produce version 1, name-based version 5, time-ordered version 7, shortened IDs or custom alphabets.
How the UUID generator works
Generation calls the browser Web Crypto crypto.randomUUID() API for every identifier. It does not build IDs from Math.random, timestamps or a counter. The browser supplies cryptographically appropriate randomness and sets the version-4 and variant bits.
The API requires a supported secure context, normally HTTPS or localhost during development. If it is unavailable, the tool reports the requirement rather than switching to a weaker random source. The batch limit bounds the amount of output and makes it easier to inspect a list before importing it.
Recognizing a UUID v4
Input
Format example only: f47ac10b-58cc-4372-a567-0e02b2c3d479
Result
Third group starts with 4 → version 4 Fourth group starts with a → supported variant 36 characters including hyphens
This fixed example explains the format. The actual generator produces different values; it does not use this example as a seed or return a canned result. Import systems may store the binary value or its textual representation, so check the expected type before uploading a text list.
When random identifiers are useful
Common uses include mock records, request correlation, object names and integration test fixtures. Generate a batch when each sample record needs a distinct identifier in the same format. Keep IDs as strings when moving them through CSV to JSON; they are identifiers, not decimal numbers.
Random UUIDs do not establish chronology. If a workflow needs sorted creation time, store that time separately instead of inferring it from v4. You can inspect a separate epoch field with the timestamp converter.
Uniqueness, security and storage considerations
Random generation makes collisions unlikely, but this tool cannot guarantee worldwide uniqueness or check your database. Applications should enforce their own uniqueness constraints and handle collisions appropriately. It does not reserve generated IDs or check them against previously generated batches.
An identifier is also not an authorization policy. Do not grant access to a resource merely because someone knows its UUID. The tool is not a password, recovery-code or session-management system. For a deterministic fingerprint of existing text, use the SHA Hash Generator; a text hash solves a different problem from generating a random identifier.
Processing and privacy
The operation runs in your browser. The tool does not send the material you enter to a processing server or automatically save it. Reset clears the form and result from the interface; it is not a secure-erasure guarantee for browser memory. Copy and download deliberately create copies outside the tool. The website itself still makes ordinary requests for its pages and scripts. See the privacy policy for the distinction.
Frequently asked questions
Will the same input produce the same UUID?
There is no input seed. Each generation requests new randomness; this is not a name-based UUID tool.
Are collisions impossible?
No. UUID v4 is designed for a very large random identifier space, but uniqueness constraints still belong in the receiving application.
Can I generate 100 IDs at once?
Yes. Set the quantity to 100 and copy or download the newline-separated result.