One such approach is combinatorial monosaccharide analysis and is most popularly used in the form of GlycoMod . GlycoMod is a Perl program designed to find all possible combinations of a glycan from an experimentally determined mass by searching a precomputed list of masses . Despite being published in 2001, it remains frequently in use but is limited by its closed source nature, and online-only access. Combinatorial mass analysis is popular in the field of metabolomics, which uses high resolution accurate mass to assign chemical formulae , and rules such as the "Seven Golden Rules" restrict the number of theoretical matches based on experimental observations . MS-based glycomics analyses have changed significantly as the monosaccharides and glycan structures observed experimentally challenge existing paradigms. This is compounded by improvements in data acquisition and bioinformatics that have allowed the glycoscience field to detect, quantify and share the data, describing more glycans than ever before .Considerable advancements have been made in the glycan bioinformatic search space including GlycReSoft , and GlycoNote , but throughput is lacking, and the monosaccharide search spaces are limited to routine and expected N-glycan structures.