OpenDataKit (ODK) and KoboToolbox are open-source applications for collecting, managing, and using data in resource-constrained environments. The tools allow for offline data collection with mobile devices in remote areas, using customized forms that users can design to meet their needs. The submission of the data to an aggregate server can be performed, when Internet connectivity is available, and data can be downloaded from the aggregate server and further processed (for example, in GIS software). Forms can be translated into multiple language, and designed to be quite complex with nested (follow-up) questions. You can record GPS location as well as capture photos, audio, and video in the forms. There are form builders available with a user interface that enables you to lay out forms without having to do any coding. Both ODK and KoboToolbox use the same data collection form template called XLSform, and forms created in one application can work in the other. The difference between the two tools is that KoboToolbox was designed to be suited for humanitarian emergencies and other challenging field environments, and provides some analysis and visualization tools for these purposes. Many earth defender communities have used both tools across the globe extensively for mapping and monitoring purposes, though frequently in collaboration with an NGO ally or technical expert who can download and process the data for the community.