The ArcGIS REST API supports responses in several formats. You specify the response format using the query parameter f. A list of valid formats is included for each of the resources and operations where f is a parameter.
Default format unless otherwise stated. The response is an HTML page.
The set of these HTML pages for each resource in the system is called the Services Directory. To view the Services Directory page for the root directory of ArcGIS Online, you would use the following URL:
Since "html" is the default value, you are not required to include this parameter in the URL. This means that the above URL is equivalent to the following URL:
The response is a JSON object in Esri JSON format.
You can also reference a callback function in the URL as follows:
If you want the JSON object to be more readable, you can use pjson. You should not include this parameter in your production applications, as it will affect performance. Use the parameter for debugging purposes only:
This format is used by many non-Esri APIs and applications. Supported by query operations in ArcGIS Server 10.4 and higher as well as hosted feature layers in ArcGIS Online:
The response is in the Protocol Buffers format.
The PBF format is binary and is thus smaller and faster for clients to parse than JSON. It is used by newer versions of some Esri APIs and applications to improve efficiency. The PBF format is supported by some feature service operations in ArcGIS Enterprise 10.7 as well as hosted feature layers in ArcGIS Online.
The response is a streamed image. No other information is included in the response.
The response is a KML document wrapped in a KMZ file.
It can be a footprint or the result of an operation. In the following example, a request is made for a KML footprint of a map service with an extent of the United States:
For more information about KML as an output option, see KML support.
The response is a context sensitive help document.
The following URL opens the help on the page that provides information about the map service resource:
The response generates a .pitemx files for map services. These files can be opened in ArcGIS Pro versions 2.3 and up.
The .pitemx file format is supported by ArcGIS Enterprise 10.7 and higher.
Generates a layer file for viewing in ArcMap