Generate v4 UUID
Generate standard version 4 UUIDs (GUIDs) securely in your browser. Create up to 1000 identifiers at once.
Runs in your browser
Your files and text are processed locally in your browser and are not uploaded.
About UUID Generator
A UUID (Universally Unique Identifier) is a 128-bit label used for information in computer systems. Version 4 UUIDs are generated using pseudo-random numbers, while Version 7 UUIDs combine a 48-bit Unix millisecond timestamp with 74 random and counter bits for optimal database B-tree index locality.
Definition: UUID v4 & v7
RFC 9562 defines UUID v4 as a 122-bit randomly generated identifier and UUID v7 as a time-ordered identifier embedding a 48-bit big-endian millisecond timestamp, represented as 32 hexadecimal digits separated by hyphens.
Inputs and Outputs
Required Inputs
- VersionSelect between UUID v4 (random) and UUID v7 (time-ordered per RFC 9562).
- CountThe number of UUIDs to generate at once (up to 1000).
Expected Outputs
- Generated UUIDsA list of generated v4 or v7 UUID strings.
- Decoded TimestampsReal-time decoded UTC timestamps for each generated UUID v7.
Who Uses the UUID Generator?
Database Primary Keys
Use sequential UUID v7 primary keys to eliminate B-tree page splits, preserve index locality, and avoid disk fragmentation.
Database Seeding
Generate a batch of UUIDs to use as mock primary keys when seeding a development database.
API Development
Generate unique transaction IDs or idempotency keys for testing API endpoints.
How to Use the UUID Generator
- 1Select UUID v4 (random) or UUID v7 (time-ordered).
- 2Enter the number of UUIDs you want to generate (between 1 and 1000).
- 3Click the 'Generate' button.
- 4Inspect decoded UTC timestamps for v7, or copy/download the raw text list.
Quick Facts
Privacy & Security Guarantee
UUID generation relies on your browser's local cryptography engine. No data is sent over the network.
Frequently Asked Questions
What is the difference between UUID v4 and UUID v7?
UUID v4 is completely random across 122 bits, which can cause B-tree index fragmentation and page splits in database primary keys. UUID v7 embeds a 48-bit millisecond timestamp (RFC 9562 §5.7) ensuring sequential time-ordering and optimal insert performance. Learn more in our <a href="/guides/uuid-v4-vs-v7" class="text-pk-primary hover:underline">UUID v4 vs v7 guide</a>.
Are the generated UUIDs truly unique?
The tool generates standard v4 and v7 UUIDs using the browser's Crypto API (crypto.randomUUID and crypto.getRandomValues), providing cryptographically secure randomness. The chance of a collision is astronomically negligible.
Are the UUIDs tracked or logged?
No. The generation happens completely locally on your device. We have no record of the UUIDs you generate.