'SurveyCTO' is a platform for mobile data collection in offline settings. The 'rsurveycto' R package uses the 'SurveyCTO' REST API < https://docs.surveycto.com/05-exporting-and-publishing-data/05-api-access/01.api-access.html> to read datasets and forms from a 'SurveyCTO' server into R as 'data.table's and to download file attachments. The package also has limited support to write datasets to a server.