Query ArcGIS Online hosted feature service by field using ArcGIS REST API

Summary

Querying data by field from an ArcGIS Online hosted feature service via the ArcGIS REST API is particularly useful when working with large datasets because it retrieves only the necessary information. This reduces the response size and improves performance.

The feature service can be queried through the REST API depending on the authorized administrative privileges. Refer to ArcGIS REST APIs: Manage API access for more information.

Procedure

1. Log in to ArcGIS Online and click Content > My Content.
2. Browse to the hosted feature layer, click More Options , and select View details.
3. On the Overview tab, under URL, click View to open the ArcGIS REST Services Directory window.

Note: 
Alternatively, in the item page, under Source, click Feature Service to open the ArcGIS REST Services Directory window.

4. In the ArcGIS REST Services Directory window, under Layers, select the feature service.
5. In the feature service's page, for Supported Operations, click Query.
6. In the Query page, specify the following parameters:
   1. For Where, specify a clause that filter results. In this example, 1=1 is specified to return all records.
   2. For Out Fields, specify the field. In this example, City is specified.

Note: 
Optionally, for the Out Fields parameter, multiple fields can be queried by separating them with commas (,) or all fields in the layer can be retrieved by specifying an asterisk (*).

7. Click Query (GET).

The result of querying the feature service by the City field is shown below.