Boulder Challenge is an Android app developed by Christian Fenzl that allows users to create and share their own boulder problems on any climbing wall, spray wall, training wall, system wall, chaos wall or boulder block. With no additional costs, users can create as many walls and boulders as they like. The app also provides users with the option to search for locations and boulder walls that have already been added or add them themselves.

Boulder Challenge is suitable for all artificial boulder walls and can also be used to save the beta of outdoor projects. Users can take a picture of the wall area they want, select an image that is already stored in the app or from the gallery of their smartphone and define the start and end of their boulder. The app also allows users to define hand and foot holds, optionally separately and explicitly for left/right if desired, and define fixed hold sequences by specifying numbering.