uuid()

Generate a UUID v7 (RFC 9562) universally unique identifier.

Signature

uuid()

None

A UUID v7 string in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

UUID v7 is a time-ordered, sortable UUID that combines:

48-bit Unix timestamp (milliseconds): Ensures UUIDs generated at the same time are monotonically increasing, making them ideal for database primary keys and indexes
74 bits of random data: Provides uniqueness within the same millisecond
Version/Variant bits: Encoded to identify it as a v7 UUID

Key advantages over UUID v4:

Time-sortable: Monotonically increasing, enabling efficient database B-tree indexing
Privacy: Doesn't embed MAC addresses like UUID v1
Database performance: Up to 35% better insertion performance in relational databases (PostgreSQL, MySQL, etc.) compared to random UUIDs
Distributed-friendly: Safe to generate independently in distributed systems

Generate a unique ID:

id = uuid()
print(id)  // "018f5c7a-d7f8-7e2c-81a3-f9c4d6e1b5a0"

Use as a database primary key:

record = {
  id = uuid(),
  name = "Alice",
  created = now()
}

Generate multiple UUIDs (each unique and time-ordered):

ids = []
for i = 1, 5 do
  push(ids, uuid())
end
print(ids)