Glycosylation is a prevalent, yet heterogeneous post translational modification of proteins with a broad range of implications in molecular biology. The heterogeneity and non-template driven nature of glycans and glycoconjugates makes them challenging to study. However, the advent of techniques like glycomics, glycoproteomics and glycoengineering have revolutionized the field of glycobiology as a fast-growing and promising research area. Emerging biochemical glycoengineering and enrichment tools, developments in MS fragmentation methods and detection software continuously open new possibilities to study glycans and glycoconjugates and make glycan research more available for the broader research community. In this dissertation we combined existing and newly developed glycomics, glycoproteomics and glycoengineering techniques to study and engineer cell-surface N-glycosylation in the context of genetic glycosylation defects and the evolution of receptor recognition in influenza A/H3N2 viruses.