anchor.diff:  :page-permalink: apim/3.x/apim_publisherguide_expression_language.html
   :page-folder: apim/user-guide/publisher
   :page-layout: apim3x
  +:page-liquid:
   
   == Overview
   
  
positive.code: is based on an API property named `my-property`:
  
  `{#request.headers[#properties['my-property']]}`
  
negative.code: == API
  === Properties
  
  As an API publisher, you can define link:{{ 'apim/3.x/apim_publisherguide_api_properties.html' | relative_url }}[properties]  for your API. These properties are
  automatically _injected_ into the expression language context to be used later.
  
  ==== Example
  
  * Get the value of the property `my-property` defined in API properties:
  `{#properties['my-property']}`
  * Get the value of the property `my-secret` defined and encrypted link:{{ 'apim/3.x/apim_publisherguide_api_properties.html' | relative_url }}[encryption] in API Properties : `{#properties['my-secret'}` to pass a secured property to your backend
  
  === Dictionaries
  
  link:{{ 'apim/3.x/apim_installguide_configuration_dictionaries.html' | relative_url }}[Dictionaries] work in a similar way to properties, but you need to specify the dictionary name as well as the property name.
  
  ==== Example
  
  