UUID v4 Generator
Generate UUID v4 instantly in your browser. No data is sent to the server.
One UUID per line. Great for seed data, fixtures, and bulk imports.
What is UUID v4?
A UUID (Universally Unique Identifier) is a 128-bit identifier designed to be unique across systems. UUID v4 is the most common variant — it’s randomly generated.
UUID v4 is widely used for database IDs, distributed systems, APIs, and client-side identifiers. This tool generates UUIDs locally in your browser.
How to use the UUID v4 Generator
- Click “Generate” to create a single UUID v4.
- Use “Copy” to copy the UUID to clipboard.
- Click “Generate 10” to create a batch list (one UUID per line).
- Use “Clear” to reset the fields.
Best practices
- UUID v4 is great for uniqueness, but can be slower for database indexes compared to sequential IDs.
- If you store UUIDs in a DB, consider using a native UUID type where available.
- Prefer lowercase UUIDs for consistency unless a system requires uppercase.
- UUIDs are not secrets — don’t use them as authentication tokens.
UUID v4 FAQ
Is UUID v4 guaranteed to be unique?
It’s not mathematically guaranteed, but collisions are extremely unlikely in practice.
Is this tool secure?
UUID v4 generation uses your browser runtime. Inputs aren’t sent to the server. For security tokens, use dedicated cryptographic token generators.
Can I use UUIDs as database primary keys?
Yes, many systems do. Keep in mind index size and fragmentation. For some workloads, time-ordered UUID variants can perform better.
Do you log or store generated UUIDs?
No. Generation happens in your browser and results are not stored.