What is a UUID?
A UUID is a 128-bit identifier designed to be unique without a central coordinator. Its familiar text form contains 32 hexadecimal characters separated into five groups.
UUID v4 versus UUID v7
UUID v4 is random. UUID v7 combines a Unix-millisecond timestamp with random bits, which makes values naturally sortable by creation time while preserving strong uniqueness characteristics.
Database usage
- UUID v4 is widely supported and useful when creation order should not be visible.
- UUID v7 can improve index locality compared with fully random identifiers.
- Store UUIDs in a native UUID or compact binary type when the database supports it.
- Treat identifiers as identifiers, not as authorization secrets.
Safe bulk generation
The quantity is capped at 5,000 per action to protect browser responsiveness. Generation uses the browser cryptographic random-number generator and generated values are not transmitted.
How to use UUID v4 & v7 Generator
- Choose UUID v4 for random identifiers or v7 for time-ordered identifiers.
- Set a quantity between 1 and 5,000.
- Choose case and hyphen presentation.
- Copy values or export TXT, CSV, or JSON.
Input and output example
Example input
Version: UUID v7; Quantity: 3; lowercase; hyphens enabledExample output
01945f20-7a10-7a21-8c4d-7b9500b15416
01945f20-7a10-7a22-a0a1-b181f6881329Troubleshooting
- Web Crypto features require a secure context in production.
- Removing hyphens changes presentation, not the underlying 128-bit value.
- Database drivers may use native UUID, binary, or text storage types.
Limitations
UUIDs provide practical uniqueness, not absolute mathematical guarantees, secrecy, authentication, or authorization. UUID v7 exposes approximate creation time.
Developer tips
- Prefer native UUID or compact binary storage where your database supports it.
- Do not use UUIDs as passwords or access tokens.
- Test index behavior with your real database workload.
Browser compatibility
Current versions of Chrome, Edge, Firefox, and Safari are supported. File, clipboard, Web Crypto, worker, canvas, and download capabilities can vary by browser and security context; the interface reports unavailable operations rather than uploading data as a fallback.