A UUID, or Universally Unique Identifier, is a 128-bit value used to label things without a central authority handing out numbers. Two services on opposite sides of the world can each mint UUIDs and still expect zero collisions. The ToolOrbit UUID Generator produces version 4 UUIDs, the random variant, using your browser's cryptographic randomness.
What a UUID v4 looks like
A UUID is written as 32 hexadecimal digits in five groups separated by hyphens. In version 4, almost all bits are random; a fixed version digit (4) and a variant digit identify the format. That leaves 122 random bits, which is why collisions are astronomically unlikely.
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version 4 variantWhy version 4 is the safe default
- No coordination needed: any client or server can generate one independently
- Cryptographically random when sourced from crypto.getRandomValues, as this tool does
- Excellent for database primary keys, request IDs, idempotency keys, and file names
- Unguessable, so they do not leak sequence information the way auto-increment IDs do
Generating IDs in bulk
Set the count and the UUID Generator produces a clean list you can copy in one click. This is ideal for seeding test data, pre-allocating keys, or populating a config file. Because generation happens entirely in your browser, no identifiers are ever transmitted or logged anywhere.
Best practices
Store UUIDs as a native UUID or binary(16) column when your database supports it, rather than as a 36-character string, to save space and speed up indexing. Use lowercase consistently, and prefer v4 unless you specifically need the time-ordering of newer schemes like UUID v7 for index locality.
UUID v4 vs v7, and when either is wrong
v4 is random and collision-safe, which makes it the default for client-generated IDs. v7 encodes the timestamp, giving roughly time-ordered values that index well in databases — the better choice when insertion order matters for performance. Avoid UUIDs entirely when the identifier must be human-readable or short (URL paths, support tickets): a 36-character ID is hostile to memory and email.
- Use v4 for rows, carts, events, anything generated outside the server.
- Use v7 in tables where sequential insert performance matters.
- Never use a random UUID as a secret — it is an identifier, not a credential.
