Backscatter tag based sensing has received a lot of attention recently due to the battery-free, low-cost, and widespread use of backscatter tags, e.g., RFIDs. Despite that, they suffer from an extensive, costly, and time-consuming redesign effort when there are changes in application requirements, such as changes in sensing targets or working frequency bands. This paper introduces a reconfigurable sensing framework, which enables us to easily reconfigure the design parameters of chipless backscatter tags for sensing different targets or working with different frequency bands, without the need for onerous design effort. To realize this vision, we capture the relationship between the application requirements and the sensing tag’s design parameters. This relationship enables us to fast and efficiently reconfigure/change an existing sensing tag design to meet new application requirements. Real-world experiments show that, by using our reconfigurable framework to flexibly redesign a tag’s parameters, the sensing tag achieves more than 92.1% accuracy for sensing four different applications and working on four different frequency bands.