About UUID & GUID Generator (RFC 4122 v4 & RFC 9562 v7)
Enterprise UUID and GUID generator conforming to RFC 4122 (Version 4 cryptographic random) and the modern RFC 9562 standard (Version 7 Unix Epoch millisecond time-ordered). Features multiple developer export formats: Standard lowercase hyphenated, uppercase, compact 32-hex (no hyphens), C# Microsoft GUID format ({...}), SQL literal (X'...'), and URN notation.
Key Capabilities & Features
- Full RFC 4122 (v4) and RFC 9562 (v7) standards compliance
- UUID v7 encodes a 48-bit Unix timestamp for optimal database B-tree index clustering
- Format toggles: Standard, Uppercase, No-Hyphen, C# GUID, SQL Hex, and URN
- Batch generation from 1 to 500 UUIDs in a single click
- Download complete batch lists as TXT or copy all to clipboard
How to Use UUID & GUID Generator (RFC 4122 v4 & RFC 9562 v7)
Select UUID Version
Choose UUID v4 (pure random) or UUID v7 (time-ordered for database primary keys).
Pick Output Format
Select standard hyphenated, uppercase, C# braced, or SQL literal.
Set Batch Count
Specify how many UUIDs you need.
Generate & Download
Click Generate to produce the batch and download or copy.
Privacy & In-Browser Execution Guarantee
100% Client-Side. Identifiers are generated using native crypto.randomUUID() / crypto.getRandomValues().
Frequently Asked Questions
Why should I use UUID v7 instead of UUID v4 in databases?
UUID v4 identifiers are completely random, which causes severe B-tree page splits and index fragmentation in relational databases (PostgreSQL, MySQL). UUID v7 embeds the millisecond timestamp in the leading bits, making them naturally monotonic and index-friendly.
What is the probability of two UUID v4 colliding?
With 122 bits of randomness, you would need to generate 1 billion UUIDs per second for roughly 85 years to have a 50% chance of a single collision.
What is the difference between UUID v4 and UUID v7?
UUID v4 is purely random (122 random bits) according to RFC 4122. UUID v7 (RFC 9562) embeds a Unix millisecond timestamp in the leading 48 bits, providing chronological time-sortability which significantly improves database B-tree index efficiency.