UUID Generator

What is a UUID?

A UUID (universally unique identifier), also called a GUID, is a 128-bit value written as 32 hex digits in five groups: 8-4-4-4-12, for example 3f2504e0-4f89-41d3-9a0c-0305e82c3301. Version 4 UUIDs are random, and the chance of two ever matching is so small that they are used as IDs in databases, APIs and software without any central registry.

Details

• Generated with your browser's cryptographic random number generator — never sent to a server.
• Version 4, RFC 4122 compliant (the 13th character is always 4).
• Options for uppercase, no hyphens and braces (used by Windows registry / C#).

How to use the UUID generator

1. Choose how many UUIDs you need (up to 500 at once).
2. Pick the format: lowercase (standard), UPPERCASE, without hyphens, or wrapped in {braces} for .NET/registry use.
3. Tap Generate, then Copy all — one UUID per line, ready to paste into a spreadsheet, database seed or config file.
4. Every ID is generated in your browser with the cryptographic random API; nothing is sent to a server or logged.

Anatomy of a version-4 UUID

3f8a1c2e-9b4d-4f7a-a1c3-7e2b9d6f0a15 — 32 hexadecimal digits in 8-4-4-4-12 groups. The first digit of the third group is always 4 (the version) and the first digit of the fourth group is 8, 9, a or b (the variant). The remaining 122 bits are random, which gives 5.3 × 10³⁶ possible values. You would need to generate a billion UUIDs every second for about 85 years to reach a 50% chance of a single duplicate.

Where UUIDs are used in India-focused projects

• Order IDs and payment reference numbers that must not reveal how many orders you have (unlike 1001, 1002…).
• Primary keys in distributed databases (PostgreSQL uuid, MongoDB, Firebase) so two servers never clash.
• Idempotency keys for UPI/payment-gateway API calls, so a retried request is not charged twice.
• File names for uploads, API keys, session tokens and tracking IDs in analytics.
• QR codes on event tickets and certificates — scan to verify against a database.

Tips and common mistakes

• UUIDs are unique, not secret — they are safe in URLs but do not use one as a password or OTP.
• Need sortable IDs? UUID v7 (time-ordered) or ULIDs index faster in databases than random v4; v4 is still the universal default.
• Store UUIDs in a native 16-byte column, not a 36-character string, to save space and speed up joins.
• For human-friendly random codes (coupons, PINs) use the Random Number Generator or Password Generator.

Frequently asked questions