Welcome to the ShorelineS wiki! With large-scale human interventions and climate change unfolding as they are now, coastal changes at decadal timescales are not limited to incremental modifications of systems that are fixed in their general geometry. Coasts often show radical changes in layout that may be catastrophic for populations living in previously stable areas. This poses severe challenges that are difficult to meet for existing models. We present a new free-form coastline model, ShorelineS, that is capable to describe drastic coastal transformations based on relatively simple principles borrowed from general coastline theory (Pelnard-Considere, 1956) and the Coastal Evolution Model (Ashton et al., 2001). As in (Hurst et al., 2015) it is vector-based, describing the coastline like a freely moving string of points, but on top of this it allows for an arbitrary number of coast sections, which can be open or closed and can interact with each other, and rocky parts or structures. This allows for a rich behaviour including shoreline undulations and formation of spits, migrating islands, merging of coastal shapes, salient and tombolos. In the paper we describe in some detail the (open-source) Matlab-based model, present some principle test cases and a field validation for the case of the Sand Engine (Stive et al., 2013). We then refer to recent developments that will be published elsewhere and sketch some approaches towards including other processes (beach-dune interactions, interactions with tidal basins, probabilistic coastline recession) in simulating coastal evolution on decadal scales, and in light of climate change and population pressure. The open-source Matlab code and documentation is freely available at www.shorelines.nl.