UUID v4 generator
Generate UUID v4 identifiers with cryptographic randomness.
Private: it runs in your browser and what you type is never sent anywhere. How to check it
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How we handle your data →How to use this tool
- Generate a version 4 UUID.
- Copy the complete string with its hyphens.
- Use uniqueness constraints in your application when the identifier must be unique.
An example you can verify
Create a version 4 identifier for test data or technical references.
Example input
Generate a UUID v4.
Expected result
Illustrative format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx.
Actual output is random; y is one of 8,9,a,b. Do not use it as a substitute for authentication.
UUID v4 generator: uses and practical guidance
A UUID v4 is a random identifier with a recognizable structure. It can support sample records, reference keys and test data that should not reuse a simple name. This tool uses the browser’s cryptographic random source and generates the requested quantity. The identifier does not necessarily contain a date or explain which resource it represents. Your application must maintain that association and determine how the value will be used.
Collision probability is very low, but absolute uniqueness among every possible identifier is not guaranteed. A database may still need a unique key constraint and a process for handling an unexpected duplicate. Generating a UUID also does not reserve it in an external service. When multiple systems share resources, define storage and validation rules in addition to choosing the identifier format. The generator supplies values rather than managing a shared registration system.
A UUID is not a password or a complete authorization mechanism. An application should verify who may access a resource even when its address contains a hard to guess identifier. Do not assume a value identifies a real person or establishes a relationship between records without additional evidence. Its purpose is a technical reference that your system assigns and retains according to explicit rules, rather than independent proof of identity.
Check the quantity generated and copy complete values, including separators. Avoid shortening identifiers without understanding how that affects the value space. Password generator serves credentials, while SHA-256 produces a fingerprint of existing text. Save the association between each UUID and its resource when preparing test data so references can be interpreted later. A well formed identifier is useful only when its surrounding data model remains clear.
A practical check before using the result
For test records, generate a list and associate each identifier with a specific row before sharing the dataset. Check complete values and confirm the receiving system accepts the hyphenated format. Avoid automatic case or separator transformations not expected by related systems. Preserve the value to resource association for reviewing later links. New generation creates new references, so it cannot reconstruct associations from an earlier sample. Save and reuse an accepted set when an import test needs stable values rather than regenerating each run. A consistent dataset lets failures be compared without introducing unrelated identifier changes, while validation in the destination still checks its actual storage requirements.
Settings and limits
Choose 1 to 100 identifiers and generate the list. Each UUID uses version 4 and the browser’s cryptographic random source.
Frequently asked questions
Is a UUID a password?
No. It is an identifier. Collision probability is extremely low, but absolute uniqueness is not guaranteed.
Is it free, and do I need to sign up?
Yes, it is free. You do not need to sign up, create an account or install an app, and there is no daily quota: open the tool and use it. The only limits are file sizes, which protect your device’s memory.
Is my data sent to any server?
No. What you type or paste is processed in your browser’s memory and is not sent to any server. You can check it in the browser’s Network tab or by going offline after the page has loaded.