Configuration is an important aspect of versatile applications. Flow provides you with configuration mechanisms which have a small footprint and are convenient to use and powerful at the same time. Hub for all configuration is the configuration manager which handles all configuration tasks like reading configuration, configuration cascading, and (later) also writing configuration.

File Locations

There are several locations where configuration files may be placed. All of them are scanned by the configuration manager during initialization and cascaded into a single configuration tree. The following locations exist (listed in the order they are loaded, i.e. later values override prior ones):

The Configuration directory of each package is scanned first. Only at this stage new configuration options must be introduced (by defining a default value).
Configuration in the global Configuration directory overrides the default settings defined in the package’s configuration directories.
There may exist a subdirectory for each application context (see Flow Bootstrap section). This configuration is only loaded if Flow runs in the respective application context.
The context specific configuration again overrides the generic settings.

The configuration manager also considers custom contexts, such as Production/Live. First, the base configuration is loaded, followed by the context specific configuration for Production and Production/Live.

Flow’s configuration system does not support placing configuration files anywhere except for in Configuration/ or one of the context directories in Configuration/. Flow only supports three top-level contexts: Production, Development, and Testing. These folders are reserved for the Flow configuration system.

Configuration Files

Flow distinguishes between different types of configuration. The most important type of configuration are the settings, however other configuration types exist for special purposes.

The configuration format is YAML and the configuration options of each type are defined in their own dedicated file:

Contains user-level settings, i.e. configuration options the users or administrators are meant to change. Settings are the highest level of system configuration. Settings have Split configuration sources enabled.
Contains routes configuration. This routing information is parsed and used by the MVC Web Routing mechanism. Refer to the Routing chapter for more information.
Contains object configuration, i.e. options which configure objects and the combination of those on a lower level. See the Object Framework chapter for more information. Objects have Split configuration sources enabled.
Contains the configuration of the security policies of the system. See the Security chapter for details. Policy has Split configuration sources enabled.
Contains a list of packages and their current state, for example if they are active or not. Don’t edit this file directly, rather use the flow command line tool do activate and deactivate packages.
Contains a list of caches which are registered automatically. Caches defined in this configuration file are registered in an early stage of the boot process and profit from mechanisms such as automatic flushing by the File Monitor. See the chapter about the Cache Framework for details. Caches have Split configuration sources enabled.
Contains configurations for Views, for example the lookup paths for templates. See the Model View Controller chapter for details.

Defining Configuration

Configuration Format

The format of Flow’s configuration files is YAML. YAML is a well-readable format which is especially well-suited for defining configuration. The full specification among with many examples can be found on the YAML website. All important parts of the YAML specification are supported by the parser used by Flow, it might happen though that some exotic features won’t have the desired effect. At best you look at the configuration files which come with the Flow distribution for getting more examples.

Example: a package-level Settings.yaml

#                                                                        #
# Settings Configuration for the Neos.Viewhelpertest Package             #
#                                                                        #

    includeViewHelpers: [alias, base]

      rootDirectory: '' # path to the XHProf library
      outputDirectory: '%FLOW_PATH_DATA%Temporary/Viewhelpertest/XHProf/' # output directory

    profilingTemplatesDirectory: '%FLOW_PATH_DATA%Temporary/Viewhelpertest/Fluidtemplates/'


Always use two spaces for indentation in YAML files. The parser will not accept indentation using tabs.

Constants and Environment

Sometimes it is necessary to use values in your configuration files which are defined as PHP constants or are environment variables. These values can be included by special markers which are replaced by the actual value during parse time. The format is %<CONSTANT_NAME>% where <CONSTANT_NAME> is the name of a constant or %env:<ENVIRONMENT_VARIABLE>%. Note that the constant or environment variable name must be all uppercase.

Some examples:

Will be replaced by the path to the public web directory.
Will be replaced by the path to the /Data/ directory.
Will be replaced by the current PHP version.
Will be replaced by this class constant’s value. Note that a leading namespace backslash is generally allowed as of PHP, but is not recommended due to CGL (stringed class names should not have a leading backslash).
Will be replaced by the value of the “HOME” environment variable.

Custom Configuration Types

Custom configuration types allow to extract parts of the system configuration into separate files.

The following will register a new type Views for configuration, using the default configuration processing handler. The code needs to be in your Package``s ``boot() method.

Example: Register a custom configuration type

$dispatcher = $bootstrap->getSignalSlotDispatcher();
$dispatcher->connect(\Neos\Flow\Configuration\ConfigurationManager::class, 'configurationManagerReady',
    function ($configurationManager) {

This will allow to use the new configuration type Views in the same way as the other types supported by Flow natively, as soon as you have a file named Views.yaml in your configuration folder(s). See Working with other configuration for details.

If you want to use a custom configuration processing loader, you can pass an implementation of \Neos\Flow\Configuration\Loader\LoaderInterface when registering the configuration or use one of the implementations found in Configuration\Loader.

Example: Register a custom configuration type and loader

$dispatcher = $bootstrap->getSignalSlotDispatcher();
$dispatcher->connect(\Neos\Flow\Configuration\ConfigurationManager::class, 'configurationManagerReady',
    function ($configurationManager) {
            new class implements LoaderInterface {
                public function load(array $packages, ApplicationContext $context) : array {
                    // load your configuration into an array $customObjectsConfiguration
                    $customObjectsConfiguration = ...
                    return $customObjectsConfiguration;

Split configuration sources

For custom types it is possible to allow for split configuration sources. For the YAML source used in Flow it allows to use the configuration type as a prefix for the configuration filenames.

Example: Register a custom configuration type, split-source

$dispatcher = $bootstrap->getSignalSlotDispatcher();
$dispatcher->connect(\Neos\Flow\Configuration\ConfigurationManager::class, 'configurationManagerReady',
    function (ConfigurationManager $configurationManager) {
            new MergeLoader(new YamlSource(), 'Models')

The above code will lead to the following files being read, sorted by name and merged if the configuration of type Models is requested:



Split configuration is supported for all configuration loader except RouteLoader(). This is because Routing uses a custom include semantic that shares the naming convention with split sources.

Accessing Settings

In almost all cases, Flow will automatically provide you with the right configuration.

What you usually want to work with are settings, which are application-specific to your package. The following example demonstrates how to let Flow inject the settings of a classes’ package and output some option value:

Example: Settings Injection

      email: ''
      name: 'John Doe'
namespace Acme\Demo;

class SomeClass {

     * @var array
    protected $settings;

     * Inject the settings
     * @param array $settings
     * @return void
    public function injectSettings(array $settings) {
        $this->settings = $settings;

     * Outputs some settings of the "Demo" package.
     * @return void
    public function theMethod() {
        echo ($this->settings['administrator']['name']);
        echo ($this->settings['administrator']['email']);


Injecting all settings creates tight coupling to the settings. If you only need a few settings you might want to inject those specifically with the Inject annotation described below.

Injection of single settings into properties

Flow provides a way to inject specific settings through the InjectConfiguration annotation directly into your properties. The annotation provides three optional attributes related to configuration injection:

  • package specifies the package to get the configuration from. Defaults to the package the current class belongs to.
  • path specifies the path to the setting that should be injected. If it’s not set all settings of the current (or
  • type one of the ConfigurationManager::CONFIGURATION_TYPE_* constants to define where the configuration is fetched from, defaults to ConfigurationManager::CONFIGURATION_TYPE_SETTINGS.


As a best-practice for testing and extensibility you should also provide setters for any setting you add to your class, although this is not required for the injection to work.

Example: single setting injection

      name: 'John Doe'
    email: ''
namespace Acme\Demo;

use Neos\Flow\Annotations as Flow;

class SomeClass

   * @Flow\InjectConfiguration(path="")
   * @var string
  protected $name;

   * @Flow\InjectConfiguration(package="SomeOther.Package", path="email")
   * @var string
  protected $email;

   * @Flow\InjectConfiguration(package="SomeOther.Package")
   * @var array
  protected $someOtherPackageSettings = array();

   * Overrides the name
  public function setName($name): void
    $this->name = $name;

   * Overrides the email
  public function setEmail($email): void
    $this->email = $email;

Working with other configuration

Although infrequently necessary, it is also possible to retrieve options of the more special configuration types. The ConfigurationManager provides a method called getConfiguration() for this purpose. The result this method returns depends on the actual configuration type you are requesting.

Bottom line is that you should be highly aware of what you’re doing when working with these special options and that they might change in a later version of Flow. Usually there are much better ways to get the desired information (e.g. ask the Object Manager for object configuration).

Configuration Cache

Parsing the YAML configuration files takes a bit of time which remarkably slows down the initialization of Flow. That’s why all configuration is cached by default, the configuration manager will compile all loaded configuration into a PHP file which will be loaded in subsequent calls instead of parsing the YAML files again.

Changes to the configuration are detected and the cache is flushed when needed. In order to flush caches manually (should that be needed), use the following command:

$ ./flow flow:cache:flush

Configuration Validation

Errors in configuration can lead to hard to spot errors and seemingly random weird behavior. Flow therefore comes with a general purpose array validator which can check PHP arrays for validity according to some schema.

This validator is used in the configuration:validate command:

$ ./flow configuration:validate --type Settings
Validating configuration for type: "Settings"

16 schema files were found:
 - package:"Neos.Flow" schema:"Settings/Neos.Flow.aop" -> is valid

 - package:"Neos.Flow" schema:"Settings/Neos.Flow.utility" -> is valid

The configuration is valid!

See the command help for details on how to use the validation.

Writing Schemata

The schema format is adapted from the JSON Schema standard; currently the Parts 5.1 to 5.25 of the json-schema specification are implemented, with the following deviations from the specification:

  • The “type” constraint is required for all properties.
  • The validator only executes the checks that make sense for a specific type, see list of possible constraints below.
  • The “format” constraint for string type has additional class-name and instance-name options.
  • The “dependencies” constraint of the spec is not implemented.
  • Similar to “patternProperties” “formatProperties” can be specified specified for dictionaries


While the configuration:validate command will stay like it is, the inner workings of the schema validation are still subject to change. The location of schema files and the syntax might be adjusted in the future, as we (and you) gather real-world experience with this.

With that out of the way: feel free to create custom schemata and let us know of any issues you find or suggestion you have!

The schemas are searched in the path Resources/Private/Schema of all active Packages. The schema-filenames must match the pattern <type>.<path>.schema.yaml. The type and/or the path can also be expressed as subdirectories of Resources/Private/Schema. So Settings/Neos/Flow.persistence.schema.yaml will match the same paths as Settings.Neos.Flow.persistence.schema.yaml or Settings/Neos.Flow/persistence.schema.yaml.

Here is an example of a schema, from Neos.Flow.core.schema.yaml:

type: dictionary
additionalProperties: false
  'context': { type: string, required: true }
  'phpBinaryPathAndFilename': { type: string, required: true }

It declares the constraints for the Neos.Flow.core setting:

  • the setting is a dictionary (an associative array in PHP nomenclature)
  • properties not defined in the schema are not not allowed
  • the properties context and phpBinaryPathAndFilename are both required and of type string

General constraints for all types (for implementation see validate method in SchemaValidator):

  • type
  • disallow
  • enum

Additional constraints allowed per type:

string:pattern, minLength, maxLength, format(date-time|date|time|uri|email|ipv4|ipv6|ip-address|host-name|class-name|interface-name)
number:maximum, minimum, exclusiveMinimum, exclusiveMaximum, divisibleBy
integer:maximum, minimum, exclusiveMinimum, exclusiveMaximum, divisibleBy
array:minItems, maxItems, items
dictionary:properties, patternProperties, formatProperties, additionalProperties