Each API in API manager is represented by an XML file. The elements of this XML file and their attributes are defined in a set of default API templates that come with the API Manager. By editing these default template definitions, you can change the synapse configuration of all APIs that are created as you want.
To edit the templates, navigate to <APIM_HOME>/repository/resources/api_templates directory in your local API Manager setup and change the necessary template XML file. For example, to change the resource content of APIs, edit api_templates_resource.xml file. This changes the resource definition of all APIs.
If you are using a distributed API Manager setup (i.e., Publisher, Store, Gateway and Key Manager components are running on separate JVMs), edit the templates on the Publisher node.