Generate a UUID in PHP

The standard library choice: ramsey/uuid

composer require ramsey/uuid

use Ramsey\Uuid\Uuid;

$id  = Uuid::uuid4()->toString();   // random v4
$id7 = Uuid::uuid7()->toString();   // time ordered v7, use for database keys
$id5 = Uuid::uuid5(Uuid::NAMESPACE_DNS, 'example.com')->toString();
$id1 = Uuid::uuid1()->toString();   // time based v1

Uuid::isValid($input);              // true or false
$u = Uuid::fromString($input);      // throws InvalidUuidStringException
$u->getVersion();                   // 4
$u->getBytes();                     // 16 bytes for BINARY(16) columns

ramsey/uuid is the package almost every PHP project uses, and Laravel depends on it. Prefer v7 for primary keys, the reasons are on the v7 page.

Laravel

use Illuminate\Support\Str;

Str::uuid();          // v4, returns a UuidInterface, cast to string when storing
Str::uuid7();         // v7, Laravel 11.x and newer
Str::orderedUuid();   // older time ordered variant, kept for compatibility

// Eloquent, Laravel 9+
use Illuminate\Database\Eloquent\Concerns\HasUuids;
class Order extends Model
{
    use HasUuids;     // v7 keys on Laravel 12, orderedUuid on 9 to 11
}

// migration
$table->uuid('id')->primary();

Symfony

composer require symfony/uid

use Symfony\Component\Uid\Uuid;

Uuid::v4();
Uuid::v7();
Uuid::isValid($input);
Uuid::fromString($input)->toRfc4122();

Without a dependency

function uuid4(): string
{
    $b = random_bytes(16);
    $b[6] = chr((ord($b[6]) & 0x0f) | 0x40);   // version 4
    $b[8] = chr((ord($b[8]) & 0x3f) | 0x80);   // variant RFC
    return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($b), 4));
}

random_bytes is cryptographically secure and available since PHP 7.

Mistakes to avoid

• uniqid() is not a UUID. It is a hex timestamp with a few extra digits, predictable and not unique across machines.
• mt_rand and rand are not secure. Use random_bytes or the package.
• Storing as VARCHAR(36) when BINARY(16) would do. Use getBytes() and fromBytes() at the boundary, or Laravel's uuid column type on PostgreSQL.

Frequently asked questions

How do I generate a UUID in PHP without Composer?

Read 16 bytes from random_bytes, set the version and variant bits, and format as hex. The snippet above does it in five lines and produces a valid v4.

Does Laravel use UUID v4 or v7?

Str::uuid() is v4. Str::uuid7() gives v7 on Laravel 11 and newer. The HasUuids trait uses v7 from Laravel 12, and orderedUuid, a custom time ordered layout, on Laravel 9 to 11.

How should I store UUIDs in MySQL from PHP?

BINARY(16) with getBytes(). It halves the storage and speeds up index lookups compared with CHAR(36). Convert back with Uuid::fromBytes when reading.