This technical presentation will examine how ArcGIS Online Services can be used within FME Workbench by using the ArcGIS REST API. With FME 2013 Safe Software started to make use of ArcGIS Online Services as Basemaps in FME Data Inspector and through various Custom Transformers like ArcGISOnlineGeocoder, ArcGISOnlineGeoenricher and ArcGISServiceAreaCalculator. This session explains the basic concepts of the ArcGIS REST API and its usage within FME Workbench. Examples illustrate how these transformers can be easily extended and completely new Custom Transformer can be created making usage of ArcGIS Online Services. Beside the usage of ArcGIS Online Services to manipulate data, Feature Services can be used to store data and publish it in ArcGIS Online Maps. Attendees will get an understanding of Custom Transfomers and ArcGIS REST API.