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This PHP extension provides the interfaces from the PSR standards as established by the PHP-FIG group. You can use interfaces provided by this extension in another extension easily - see this example.

As of v1.2 of the extension, classes are defined in the PsrExt namespace and aliased into the Psr namespace.


PSR Reference
PSR-3 psr/log *
PSR-6 psr/cache
PSR-7 psr/http-message
PSR-11 psr/container
PSR-13 psr/link
PSR-14 psr/event-dispatcher
PSR-15 psr/http-server-handler
PSR-15 psr/http-server-middleware
PSR-16 psr/simple-cache
PSR-17 psr/http-factory
PSR-18 psr/http-client


Linux / macOS

Prerequisite packages are:

  • PHP development headers and tools, php >= 7.3
  • gcc >= 4.4 | clang >= 3.x | vc >= 11
  • GNU make >= 3.81
  • automake
  • autoconf

You will need the PHP development headers. If PHP was manually installed, these should be available by default. Otherwise, you will need to fetch them from a repository.

git clone
cd php-psr
make test
sudo make install

If you have specific PHP versions running:

git clone
cd php-psr
./configure --with-php-config=/usr/local/bin/php-config
make test
sudo make install

Add the extension to your php.ini:

echo | tee -a /path/to/your/php.ini

Finally, restart the web server.

PECL / Windows

You may also be able to install this extension via PECL:

pecl install psr

or by downloading a DLL from PECL or and placing it in the appropriate directory.

Nix / NixOS

nix-env -i -f

with a custom version of PHP:

nix-env -i -f --arg php '(import <nixpkgs> {}).php71'

or, in a .nix file:

(import <nixpkgs> {}).callPackage (import (fetchTarball {
  url =;
  sha256 = "1c4jc09d46ac43kkckil8l76is973czwp0g6vhpnv5105l7z3zgi";
})) {}

Using with composer

In your project, you can prevent the installation of the unnecessary composer packages provided by this extension by adding the following to your composer.json. You will need to make sure the extension is installed and enabled in your PHP configuration. You may also want to consider leaving them installed to provide stubs to your IDE. This configuration is not suitable for a library published to packagist.

Note: LoggerInterfaceTest and TestLogger from psr/log are not implemented. If you use these classes, you should keep psr/log installed (discussion).

    "name": "sample/app",
    "require": {
        "ext-psr": "*"
    "provide": {
        "psr/log": "1.0.0",
        "psr/cache": "1.0.0",
        "psr/http-message": "1.0.0",
        "psr/container": "1.1.1",
        "psr/link": "1.0.0",
        "psr/event-dispatcher": "1.0.0",
        "psr/http-server-handler": "1.0.0",
        "psr/http-server-middleware": "1.0.0",
        "psr/simple-cache": "1.0.0",
        "psr/http-factory": "1.0.0",
        "psr/http-client": "1.0.0"

This will use this PHP extension instead of downloading from packagist.



This project is open source software licensed under the Simplified BSD License. See the file for more information.

PSR Interfaces: Copyright (c) 2012-present PHP Framework Interoperability Group.


PHP extension providing the accepted PSR interfaces








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