SugarSketcher is an intuitive and fast JavaScript interface module for online drawing of glycan structures in the popular Symbol Nomenclature for Glycans (SNFG) notation and exporting them to various commonly used formats encoding carbohydrate sequences (e.g., GlycoCT) or quality images (e.g., svg). It does not require a backend server or any specific browser plugins and can be integrated in any web glycoinformatics project. SugarSketcher allows drawing glycans both for glycobiologists and non-expert users. The "quick mode" allows a newcomer to build up a glycan structure having only a limited knowledge in carbohydrate chemistry. The "normal mode" integrates advanced options which enable glycobiologists to tailor complex carbohydrate structures. The source code is freely available on GitHub and glycoinformaticians are encouraged to participate in the development process while users are invited to test a prototype available on the ExPASY web-site and send feedback.

CEITEC⁻Central European Institute of Technology Masaryk University Brno 625 00 Brno Bohunice Czech Republic National Centre for Biomolecular Research Faculty of Science 625 00 Brno Bohunice Czech Republic

Polytech Nice Sophia Campus SophiaTech 06903 Sophia Antipolis France

Proteome Informatics Group SIB Swiss Institute of Bioinformatics 1211 Geneva Switzerland Computer Science Department University of Geneva 1211 Geneva Switzerland

Proteome Informatics Group SIB Swiss Institute of Bioinformatics 1211 Geneva Switzerland Computer Science Department University of Geneva 1211 Geneva Switzerland Section of Biology University of Geneva 1211 Geneva Switzerland

Zelinsky Institute of Organic Chemistry Russian Academy of Sciences Laboratory of Carbohydrate Chemistry 119991 Moscow Russia

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