#UUID & ULID

Lift\Support\Uuid generates cryptographically secure identifiers. All formats use random_bytes() for their random component.

#Formats at a glance

#UUID v4 — random

122 bits of cryptographic randomness. No time component — maximally opaque.

use Lift\Support\Uuid;

$id = Uuid::v4();
// e.g. "550e8400-e29b-41d4-a716-446655440000"

#UUID v7 — time-ordered

The first 48 bits encode a millisecond-precision Unix timestamp. Subsequent UUIDv7 values sort lexicographically, making them ideal for database primary keys (B-tree friendly, no index fragmentation).

$id = Uuid::v7();
// e.g. "018f8e0d-1c2a-7xxx-xxxx-xxxxxxxxxxxx"
//       ^^^^^^^^ ms timestamp prefix

// With a specific timestamp (useful for tests)
$id = Uuid::v7(ms: 1_718_700_000_000);

#Database schema

-- MySQL / MariaDB
CREATE TABLE users (
    id       BINARY(16)   NOT NULL PRIMARY KEY DEFAULT (UUID_TO_BIN(UUID(), 1)),
    -- or store as CHAR(36) if BINARY(16) is too inconvenient
    name     VARCHAR(255) NOT NULL
);

Store as BINARY(16) using the binary helpers:

// Store
$binary = Uuid::toBinary(Uuid::v7());

// Retrieve
$uuid = Uuid::fromBinary($row['id']);

#ULID — Universally Unique Lexicographically Sortable Identifier

26-character Crockford base32 string. 10-char time prefix (ms precision) + 16-char random suffix.

Advantages over UUID:

• 26 vs 36 characters — more compact
• No dashes — cleaner in URLs, logs, and CLI output
• Case-insensitive
• Excludes ambiguous characters (I, L, O, U)

$id = Uuid::ulid();
// e.g. "01ARZ3NDEKTSV4RRFFQ69G5FAV"

// Specific timestamp
$id = Uuid::ulid(ms: 1_718_700_000_000);

#Validation

Uuid::isValid('550e8400-e29b-41d4-a716-446655440000'); // true
Uuid::isValid('not-a-uuid');                           // false

Uuid::isValidUlid('01ARZ3NDEKTSV4RRFFQ69G5FAV'); // true
Uuid::isValidUlid('INVALID');                     // false

isValid() accepts UUID versions 1–8 (case-insensitive).

#Binary encoding

Store UUIDs efficiently in a BINARY(16) column (half the storage of CHAR(36)):

// On write
$binary = Uuid::toBinary($uuid);  // 16 raw bytes

// On read
$uuid = Uuid::fromBinary($binary);  // back to "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"

#Choosing the right format

New project, DB primary keys?   → UUID v7  (sortable, B-tree friendly)
URL slugs, log correlation IDs? → ULID     (compact, URL-safe)
Compatibility with existing UUIDs? → UUID v4