GlyTouCan v4: a redesigned interface and expanded functionality for the international glycan structure repository

GlyTouCan (https://glytoucan.org) is the international, species-neutral glycan structure repository that assigns stable, globally unique accession numbers to glycan structures independently of the experimental method used to determine them. Here, we describe GlyTouCan version 4, released on June 22, 2026, which introduces a completely redesigned user interface with substantially faster browsing and searching, including a new "archetype" view that groups registrations that differ only in the anomeric or ring form of the reducing-end residue together for clearer filtering of the >256,000 glycans now registered. Version 4 provides an improved graphical structure input, via the updated browser-embedded GlycanBuilder application, for both searching and registering structures. Users may now sign in with an ORCID ID in addition to a Google account, and all previously released v3 REST API endpoints remain fully backward compatible. Version 4 also introduces a framework for industry affiliates, providing a structured pathway for commercial organizations that work with or synthesize glycans, while all existing academic database-partner relationships are maintained. GlyTouCan remains freely available to all users without charge, login, or registration for browsing and searching. We also summarize the repository's data content, which spans >600 monosaccharide types and, judging from these, includes many glycans of probable bacterial or plant origin.