Vendor binaries and the vendor/bin directory

What is a vendor binary?

Any command line script that a Composer package would like to pass along to a user who installs the package should be listed as a vendor binary.

If a package contains other scripts that are not needed by the package users (like build or compile scripts) that code should not be listed as a vendor binary.

How is it defined?

It is defined by adding the bin key to a project's composer.json. It is specified as an array of files so multiple binaries can be added for any given project.

    "bin": ["bin/my-script", "bin/my-other-script"]

What does defining a vendor binary in composer.json do?

It instructs Composer to install the package's binaries to vendor/bin for any project that depends on that project.

This is a convenient way to expose useful scripts that would otherwise be hidden deep in the vendor/ directory.

What happens when Composer is run on a composer.json that defines vendor binaries?

For the binaries that a package defines directly, nothing happens.

What happens when Composer is run on a composer.json that has dependencies with vendor binaries listed?

Composer looks for the binaries defined in all of the dependencies. A symlink is created from each dependency's binaries to vendor/bin.

Say package my-vendor/project-a has binaries setup like this:

    "name": "my-vendor/project-a",
    "bin": ["bin/project-a-bin"]

Running composer install for this composer.json will not do anything with bin/project-a-bin.

Say project my-vendor/project-b has requirements setup like this:

    "name": "my-vendor/project-b",
    "require": {
        "my-vendor/project-a": "*"

Running composer install for this composer.json will look at all of project-a's binaries and install them to vendor/bin.

In this case, Composer will make vendor/my-vendor/project-a/bin/project-a-bin available as vendor/bin/project-a-bin. On a Unix-like platform this is accomplished by creating a symlink.

What about Windows and .bat files?

Packages managed entirely by Composer do not need to contain any .bat files for Windows compatibility. Composer handles installation of binaries in a special way when run in a Windows environment:

  • A .bat file is generated automatically to reference the binary
  • A Unix-style proxy file with the same name as the binary is generated automatically (useful for Cygwin or Git Bash)

Packages that need to support workflows that may not include Composer are welcome to maintain custom .bat files. In this case, the package should not list the .bat file as a binary as it is not needed.

Can vendor binaries be installed somewhere other than vendor/bin?

Yes, there are two ways an alternate vendor binary location can be specified:

  1. Setting the bin-dir configuration setting in composer.json
  2. Setting the environment variable COMPOSER_BIN_DIR

An example of the former looks like this:

    "config": {
        "bin-dir": "scripts"

Running composer install for this composer.json will result in all of the vendor binaries being installed in scripts/ instead of vendor/bin/.

You can set bin-dir to ./ to put binaries in your project root.

© Nils Adermann, Jordi Boggiano
Licensed under the MIT License.