README

A PHP library for generating and working with identifiers

About

ramsey/identifier is a PHP library designed for generating, parsing, and working with a variety of unique identifiers. It provides an object-oriented interface for several industry-standard identifier formats—including UUIDs, ULIDs, and Snowflake IDs. This library emphasizes standards-compliance, interoperability, and developer ergonomics, making it easy to create and manipulate identifiers in modern PHP applications.

This project adheres to a code of conduct. By participating in this project and its community, you are expected to uphold this code.

Installation

Install this package as a dependency using Composer.

composer require ramsey/identifier

Usage

ramsey/identifier provides ways to generate industry-standard identifiers, such as UUIDs, ULIDs, and Snowflake IDs. You can do this using the provided factory classes:

use Ramsey\Identifier\Snowflake\GenericSnowflakeFactory;
use Ramsey\Identifier\Snowflake\Epoch;
use Ramsey\Identifier\Ulid\UlidFactory;
use Ramsey\Identifier\Uuid\UuidFactory;

// Create a UUID.
$uuid = (new UuidFactory())->create();

// Create a ULID.
$ulid = (new UlidFactory())->create();

// Create a Snowflake.
$snowflake = (new GenericSnowflakeFactory(1, Epoch::Unix))->create();

With UuidFactory, you may create UUIDs of different versions:

use Ramsey\Identifier\Uuid\NamespaceId;

$factory = new UuidFactory();

// Create random UUIDs (version 4).
$uuidV4 = $factory->v4();

// Create named-based UUIDs using SHA-1 hashing (version 5).
$uuidV5 = $factory->v5(NamespaceId::Url, 'https://example.com/post/1234');

// Create Unix Epoch time-based UUIDs (version 7).
$uuidV7 = $factory->v7();

You may also parse existing identifiers:

// Parse a UUID.
$uuid = (new UuidFactory())->createFromString('01977bea-d1c0-7154-87bb-6550974155c2');

// Parse a ULID.
$ulid = (new UlidFactory())->createFromString('01JXXYNME0E5A8FEV5A2BM2NE2');

// Parse a Snowflake ID.
$snowflake = (new GenericSnowflakeFactory(1, Epoch::Unix))->createFromInteger(7340580095540599922);

Each of these identifiers happen to contain the same timestamp, which we can retrieve:

echo $uuid->getDateTime()->format('Y-m-d H:i:s.v P') . "\n";
echo $ulid->getDateTime()->format('Y-m-d H:i:s.v P') . "\n";
echo $snowflake->getDateTime()->format('Y-m-d H:i:s.v P') . "\n";

This will print:

2025-06-17 03:24:36.160 +00:00
2025-06-17 03:24:36.160 +00:00
2025-06-17 03:24:36.160 +00:00

The UUID and ULID shown above have the same underlying byte values. Every version 7 UUID can also be expressed as a ULID, but not every ULID can be converted into a version 7 UUID. Similarly, Snowflake identifiers and ULIDs both encode a timestamp and randomness, but their formats are not directly interchangeable with UUIDs or each other.

if ($uuid->equals($ulid)) {
    echo "They are equal!\n";
}

if ($uuid->equals($snowflake)) {
    echo "The timestamp is the same, but they aren't equal.\n"
}

Contributing

Contributions are welcome! To contribute, please familiarize yourself with CONTRIBUTING.md.

Coordinated Disclosure

Keeping user information safe and secure is a top priority, and we welcome the contribution of external security researchers. If you believe you've found a security issue in software that is maintained in this repository, please read SECURITY.md for instructions on submitting a vulnerability report.

Copyright and License

ramsey/identifier is copyright © Ben Ramsey and Contributors and licensed for use under the terms of the GNU Lesser General Public License (LGPL-3.0-or-later) as published by the Free Software Foundation. Please see COPYING.LESSER, COPYING, and NOTICE for more information.