UUID Generator
Use a random identifier when you need sample records, correlation values or test data without a sequence counter. Each UUID generated here uses cryptographically secure browser randomness, with the version and variant bits set for UUID v4. Generate a single value or a batch of up to fifty, then copy one item or the newline-separated list. These identifiers are not passwords, access tokens or proof of identity. Your application still needs to decide how identifiers are stored and whether they can be exposed publicly.
Your workspace
Runs locally in your browserResult
Your input is processed locally in your browser unless explicitly stated otherwise. Inputs are not saved by this tool.
How to use this tool
Choose a batch size and generate. Copy an individual identifier or the complete newline-separated batch.
Example
Input
Batch size: 1Output
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxxWhat does this tool do?
A version 4 UUID is a 128-bit identifier with reserved version and variant bits. The remaining 122 bits are randomly generated.
Common mistakes and limitations
UUIDs have a very low collision probability, not a mathematical uniqueness guarantee. Enforce uniqueness in storage where it matters.
What a version 4 UUID contains
A UUID is a 128-bit identifier usually printed as hexadecimal groups separated by hyphens. Version 4 reserves some bits for the version and variant and uses the remaining bits for randomness. This generator uses the browser’s cryptographic random source. The recognizable 4 in the version position describes the format; it does not encode a creation time or a database sequence.
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
y uses the UUID variant bitsRandom identifiers and database keys
UUIDs can be created independently by different clients, which is useful for distributed records and fixtures. Integer IDs are smaller and often easier to sort and inspect within a single database. Random UUIDs have different index locality and storage costs, so choose a key strategy for your workload rather than assuming one format is always faster. If a stored collection requires uniqueness, retain a database uniqueness constraint even when collision probability is very low.
Uniqueness is not secrecy
A value being difficult to guess does not make it a complete access-control mechanism. An exposed UUID may identify an order or document, but the server must still authorize access. Do not use a UUID alone as proof that a request is trusted. Copy generated identifiers without changing their hyphens when a downstream validator expects canonical text, and avoid confusing UUID v4 with time-ordered versions that carry different properties.
Use IDs consistently across systems
Some systems accept uppercase UUID text while others normalize to lowercase. Compare parsed identifiers or a documented canonical form rather than depending on presentation differences. UUIDs do not contain an inherent user permission or a reliable sort order by creation time. If you need a chronological list, store a separate creation timestamp. For mock data, label generated values as fixtures so they are not confused with actual records.
Frequently asked questions
Are these sequential IDs?
No. UUID v4 values are random and do not encode a creation time.
Related tools
Random String Generator
Generate configurable random strings for test data and development identifiers.
Open tool Security & GeneratorsPassword Generator
Create random passwords with configurable character sets.
Open tool Security & GeneratorsSHA Hash Generator
Generate SHA-256, SHA-384 or SHA-512 hex digests from UTF-8 text locally.
Open tool