Seeding a database table
Before
Needed 500 unique IDs for test data
After
500 UUID v4s generated in one shot
Copied the whole list, pasted into a SQL insert. Saved an hour of scripting.
All Tools
UUID Generator – UUID v4 and GUID Generator
I built this when I was seeding a database and needed 500 unique IDs at once. Most online generators only give you one at a time. This one does bulk generation, lets you pick uppercase or hyphen-free, and doesn't require an account.
100% free, no signup
Your files are processed in your browser and never uploaded to any server.
A note from me
The v4 UUIDs here use the browser's crypto API — the same randomness source that secure applications use. For database seeding, generate in batches of 100 at a time; the page stays fast and you don't lose work if the browser hiccups. One thing I noticed: PostgreSQL and MySQL both handle UUIDs well, but for MySQL, store them as BINARY(16) rather than CHAR(36) if the table will be large — it saves significant index space.
— Mirza Noman Baig
How to use this tool
- 1Pick how many UUIDs you want.
- 2Choose format — standard, uppercase, or without hyphens.
- 3Click Generate.
- 4Copy individual UUIDs or copy the whole list.
Real results from testing
These are actual measurements from using this tool, not estimates.
API resource identifiers
Before
Sequential integer IDs exposed in URLs
After
UUIDs as primary keys in the public API
Sequential IDs made it easy to guess other records. UUIDs fixed that. This tool generated 1000 test IDs for load testing.
Test data for a frontend
Before
Mock objects all had the same fake ID
After
Each mock object got a unique UUID
React keys behaved correctly with real unique values. Caught a bug the fake IDs were hiding.
UUID Generator features
Single or bulk generation
Generate one UUID or hundreds at once, depending on what you need.
Format options
Standard, uppercase, or hyphen-free — pick the format your app expects.
Cryptographically random
Uses the browser's secure random API — the same source trusted for security tokens.
No signup, no tracking
Generate as many as you need, as often as you need, without an account.
Frequently asked questions
What's the difference between UUID and GUID?+
They're the same thing. UUID is the general term; GUID is what Microsoft calls it. Both are 128-bit identifiers.
Are these UUIDs cryptographically random?+
Yes. They use the browser's crypto.getRandomValues, which is the same source browsers use for security tokens.
Can I generate UUIDs without hyphens?+
Yes. Choose the hyphen-free format — useful for compact storage or URLs.
Do you store the generated UUIDs?+
No. Everything runs in your browser. Nothing gets sent to a server.
Are UUIDs safe for database primary keys?+
Yes. UUID v4 is fine for most databases. For very large tables, use PostgreSQL's native UUID type or MySQL's BINARY(16) to save space.