Database identifiers
Create IDs before an entity is inserted, which can simplify offline and distributed workflows.
Developer Tools
UUID Generator Online Free
Generate random UUID and GUID values online for free. Create UUID v4 identifiers for databases, APIs, applications, test data and development workflows directly in your browser.
Developer authority guide
Use UUID Generator with confidence
Generate UUID v4 identifiers for database records, distributed systems, API resources and test data. UUIDs reduce coordination requirements between services, but they do not guarantee that a value is secret, unpredictable for security purposes or valid for a particular business entity.
✓ Runs in your browser
✓ No account required
✓ Free developer utility
✓ Mobile and desktop ready
Practical use cases
API resources
Assign non-sequential public identifiers to resources and correlation records.
Test fixtures
Generate unique values for automated tests, examples and import files.
Distributed tracing
Create correlation identifiers across services, queues and logs.
Recommended workflow
- 1
Choose how many UUID v4 values you need.
- 2
Generate the identifiers.
- 3
Copy them without extra punctuation or spaces.
- 4
Validate storage type, casing and formatting expectations in the destination system.
Developer correctness
Validate syntax, semantics and runtime assumptions
Developer utilities can transform representation without proving that the result is correct for a production system. Syntax, encoding, runtime-specific rules, schemas and security context all matter. Treat browser output as a fast inspection aid, then validate it in the target language, framework or deployment environment.
Syntax vs semantics
A value can be syntactically valid while still violating an API contract or business rule.
Encoding
Unicode, escaping and byte representation can change how data is interpreted across systems.
Runtime differences
Regex, date parsing, SQL and serialization behaviour can vary between engines and libraries.
Security context
Encoding, hashing and formatting do not replace validation, authorization or safe APIs.
What the operation can change
- Formatting should preserve values but may normalise whitespace.
- Minification removes presentation whitespace and can make debugging harder.
- Encoding changes representation, not trustworthiness or confidentiality.
- Generated code still needs review for naming, nullability and framework conventions.
Domain-specific verification
- Run the result through the destination parser or compiler.
- Test Unicode, empty values, nulls and deeply nested inputs.
- Compare behaviour against the production runtime and version.
- Never paste secrets, access tokens or confidential payloads into untrusted tools.
Engineering review
Prepare, verify and troubleshoot the result
Before using the tool
- ✓ Confirm which UUID version the destination expects.
- ✓ Decide whether identifiers need randomness, ordering or determinism.
- ✓ Do not infer business meaning from a generated UUID.
Before using the output
- ✓ Validate the required text format and casing.
- ✓ Check database and API field lengths.
- ✓ Generate identifiers at the system boundary responsible for uniqueness.
ProblemPractical check
Database rejects the UUIDCheck braces, hyphens, casing and the database column type.
IDs fragment an indexReview ordered UUID strategies or database-specific sequential identifiers.
Duplicate concernUse a cryptographically secure UUID implementation and avoid truncating the value.
Implementation notes
- • UUIDs provide identifiers, not authorization or secrecy.
- • Version and generation strategy affect ordering and privacy characteristics.
Common mistakes to avoid
Treating UUIDs as secrets
An identifier can be exposed and should not replace authorization checks.
Using strings inefficiently
Many databases provide native UUID or uniqueidentifier types with better validation.
Mixing versions unknowingly
Different UUID versions have different generation properties.
Ignoring index design
Random values can affect clustered index locality in high-write databases.
Professional tips
- ✓Use native database UUID types where available.
- ✓Keep authorization independent from identifier obscurity.
- ✓Document the UUID version used by each system.
- ✓Use a consistent lowercase or uppercase display convention.
Frequently asked questions
Are UUID and GUID the same?
GUID is Microsoft's commonly used name and representation for identifiers compatible with the UUID concept.
Can two UUID v4 values collide?
A collision is theoretically possible but extraordinarily unlikely when generated correctly.
Is UUID v4 sortable by creation time?
No. UUID v4 is random. Time-sortable identifier formats or other UUID versions may be better for that requirement.
Should UUIDs be stored with hyphens?
The display form usually contains hyphens, but storage depends on the database's native type and application conventions.
Can a UUID identify a user securely?
It can identify a record, but the application must still enforce authentication and authorization.
Why use UUIDs instead of integers?
They can be generated independently across systems and are less predictable in public URLs, though they use more storage.