Cinderplot is a small, fast, grammar-inspired plotting tool written in C. It turns a CSV/TSV (plain or gzipped) into publication-quality PDF, SVG or PNG graphics via Cairo. Five modes, chosen by the verbs used: a ggplot2-flavoured grammar (aes/geom_*, facets, scales, themes), a wheatmap-style matrix mode (composable heatmaps, annotations, Ward clustering, dendrograms, legends), a genome locus browser of stacked tracks (bedGraph/BED/BEDPE/BED12, tabix), a Newick tree mode, and a circlize-style chord diagram. Dependencies are deliberately minimal: Cairo and zlib.