Understanding the structure–function relationship of carbohydrates in biological systems is a major challenge. Such investigations require fast and reliable access to structurally-defined oligosaccharides. To date, oligosaccharide synthesis has been considered technically difficult and only parts of the synthetic process have been automated using solution and solid-phase techniques. Here, we describe a versatile platform integrating a new synthesis strategy and a fully-automated oligosaccharide synthesizer. Structurally diverse conjugation-ready oligosaccharides can be generated for the creation of glycoconjugates and microarrays. Biologically-significant oligosaccharides of increasing length, structural complexity, and chemical diversity were produced, including glycans found on the surfaces of pathogenic bacteria, and those with integral roles in inflammatory and immune responses.