UUID / GUID Generator
Generate UUID v4, v1, and v7 online. Batch up to 100, copy or download as TXT.
Click Generate to create UUIDs.
What is a UUID generator?
A UUID (Universally Unique Identifier) is a 128-bit label used as a unique ID in databases, APIs, and distributed systems. Versions differ in how randomness and time are mixed into the value.
Choose v4 for most apps, v7 when database indexes should stay time-ordered, and v1 when you need a timestamp inside the ID. Match format (case, hyphens, braces) to your API or column type.
Everyday examples
Database primary key
Generate a v4 UUID when inserting a new row in PostgreSQL or MongoDB.
API request ID
Attach a unique v7 UUID to each request for sortable logs.
Test fixtures
Batch 50 lowercase UUIDs without hyphens for unit tests.
How to use this UUID generator
Pick a version, set format and count, then generate. All values are created locally in your browser.
When is this useful?
Backend & DB
Primary keys, correlation IDs, and migration seeds.
Frontend dev
Mock IDs in React/Vue prototypes without a server.
DevOps & QA
Bulk UUIDs for load tests or config templates.
Common mistakes
Wrong version
Use v4 for general random IDs; v7 when you need time-ordered values in indexes.
Case sensitivity
Some systems treat uppercase and lowercase UUIDs differently in string compares.
v1 vs real MAC
Our v1 uses a random node field – fine for apps, not a hardware MAC address.
Version overview
Each version follows RFC 4122 (v4, v1) or RFC 9562 (v7). Example shape only – values change every click.
| Version | Use case | Example shape | Notes |
|---|---|---|---|
| v4 | Random ID | xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx | crypto.randomUUID() |
| v1 | Time-based | xxxxxxxx-xxxx-1xxx-yxxx-xxxxxxxxxxxx | Timestamp + random node |
| v7 | Sortable DB key | xxxxxxxx-xxxx-7xxx-yxxx-xxxxxxxxxxxx | Unix ms + random |
| Batch export | Count 25, lowercase | 25 lines in textarea | QA fixtures or migration seed files |
| .NET GUID | Braces on, v4 | {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} | C# Guid.Parse and legacy Windows APIs |
Generation details
- v4
crypto.randomUUID() or 122 random bits with version 4 / variant bits set - v1
100-ns timestamp since UUID epoch + random clock_seq and node bytes - v7
48-bit Unix timestamp (ms) + 12 random bits + 62 random bits (RFC 9562) - Randomness
crypto.getRandomValues only – no Math.random
Key UUID terms
UUID
128-bit identifier, usually shown as 32 hex digits in five groups.
GUID
Microsoft name for the same identifier format as UUID.
Variant bits
Fixed pattern in byte 8 so parsers know this is a standard UUID.
Batch
Generate up to 100 UUIDs at once and copy or download as plain text.
Frequently Asked Questions
UUID versions, formats, and privacy explained.
Is data sent to a server?
No. UUIDs are generated entirely in your browser.
Which version should I use?
v4 for most cases. v7 for database indexes that benefit from time order. v1 when you need a timestamp embedded in the ID.
Are v1 UUIDs guaranteed unique?
Collision risk is extremely low for practical use, but v1 here uses a random node – not a factory MAC address.
Can I remove hyphens?
Yes – choose the no-hyphens format or wrap values in braces for .NET-style GUID strings.
About these results
Outputs follow standard UUID layout. Always verify format requirements of your target system (case, hyphens, braces).