Configuring PHP


PHP will read its configuration from:

  • /opt/bref/etc/php/php.ini (PHP's official production configuration)
  • /opt/bref/etc/php/conf.d/bref.ini (Bref's optimizations for Lambda)

These files cannot be customized.

Customizing php.ini

You can create your own php.ini to customize PHP's configuration:

  1. create a php/conf.d/ subdirectory in your project
  2. create a php.ini file inside that directory (the name of the file does not matter, it must have an .ini extension)

PHP will automatically include any *.ini file found in php/conf.d/ in your project.

Customizing php.ini using a custom path

If you want PHP to scan a different directory than php/conf.d/ in your project, you can override the path by setting it in the PHP_INI_SCAN_DIR (opens in a new tab) environment variable.


PHP_INI_SCAN_DIR must contain an absolute path. Since your code is placed in /var/task on AWS Lambda, the environment variable should contain something like /var/task/my/different/dir.

Learn how to declare environment variables by reading the Environment Variables guide.

Customizing php.ini in extra layers

If you are using Lambda layers, for example to use custom PHP extensions, you can override the default php.ini by placing your own configuration file in /opt/bref/etc/php/conf.d/.

Make sure to give a unique name to your .ini file to avoid any collision with other layers.


Bref strives to include the most common PHP extensions. If a major PHP extension is missing please open an issue to discuss it.

Built-in extensions

The following extensions are installed and enabled by default in Bref runtimes:

Extensions installed but disabled by default

The following extensions are installed in Bref runtimes, but disabled by default:

You can enable these extensions by loading them in php/conf.d/php.ini (as mentioned in the section above), for example:


Extra extensions

Due to space limitations in AWS Lambda, Bref runtimes cannot include every possible PHP extensions. These additional PHP extensions can be included as separate AWS Lambda layers.

All extra PHP extensions are found in brefphp/extra-php-extensions (opens in a new tab).

Contributions to add more PHP extensions are welcomed.

Custom extensions

It is also possible to provide your own extensions via custom AWS Lambda layers (opens in a new tab).

This guide is really raw, feel free to contribute to improve it.

To create your custom layer, you will need to:

  • compile the extension (and any required libraries) in the same environment as AWS Lambda and Bref
  • include the compiled extension (and required libraries) in a layer
  • upload the layer to AWS Lambda
  • include the in your project
  • enable the extension in a custom php.ini

To compile the extension, Bref provides the bref/build-php-* Docker images. Here is an example with Blackfire:

FROM bref/build-php-80:2
RUN curl -A "Docker" -o /tmp/ -L -s ""
# Build the final image from the amazon image that is close to the production environment
# Copy things we installed to the final image
COPY --from=0 /tmp/ /opt/bref-extra/

The .so extension file can then be retrieved in /opt/bref-extra/ If you installed system libraries, you may also need to copy them to the image.

See brefphp/extra-php-extensions (opens in a new tab) for more examples.

Custom vendor path

Bref automatically requires vendor dependencies from the default vendor/autoload.php path.

If your Composer dependencies are installed elsewhere, you can customize that path via the BREF_AUTOLOAD_PATH environment variable.

    # ...
        BREF_AUTOLOAD_PATH: '/var/task/foo-bar/vendor/autoload.php'

The path must start with /var/task, which is the directory where projects are installed on AWS Lambda.