"Within the survey context, a geofence can be defined as a geographical area that triggers a survey invitation when an individual enters the area, dwells in the area for a defined amount of time or exits the area. Geofences may be used to administer context-specific surveys, such as an evaluation survey of a shopping experience at a specific retail location. While geofencing is already used in other contexts (e.g., marketing and retail), this technology seems so far to be underutilized in survey research. We implemented a geofence survey in a smartphone data collection project and geofenced 410 job centers with the Google Geofence API. Overall, the app sent 230 geofence-triggered survey invitations to 107 participants and received 224 responses from 104 participants. This article provides an overview of our geofence survey, including our experiences analyzing the data. We highlight the limitations in our design and examine how those shortcomings affect the number of falsely triggered surveys. Subsequently, we formulate the lessons learned that will help researchers improve their own geofence studies." (Author's abstract, IAB-Doku)