: Despite recent advances in map-generalization tools and theories, this work has been slow to find its way into the hands of the map-making public. Mapshaper.org is a free-touse generalization web service developed to help mapmakers simplify and smooth their vector linework using a suite of visual-editing tools. This paper details some of the technical barriers that had to be solved to enable real-time WYSIWIG map generalization: (1) optimized distribution of work between client and server, (2) support for Douglas-Peucker, VisvalinghamWhyatt, and weighted Visvalingham-Whyatt, and (3) data compression and file-format optimization for near real-time editing capabilities.