MassBank: an open and FAIR mass spectral data resource

The open spectral library MassBank (https://massbank.jp/) started in 2006 in Japan, as one of the first open source and open access cross-vendor mass spectral libraries. The first dedicated European MassBank server (https://massbank.eu/) was launched in 2011, adding spectra from compounds of environmental relevance to complement the original metabolomics focus. Recent developments boosted the FAIRness of MassBank data, and a redesigned web interface with modern architecture was launched in 2025. All records are under version control, and versioned releases are pushed to an independent data repository with digital object identifier assigned to each data release. Semantic metadata integrates the spectral data into the world of linked open data. The record format enables many downstream studies, and records are validated by an automated pipeline to ensure data quality upon submission and review existing records. The SPectraL hASH was added for spectral content-based access. MassBank is cross-integrated in several resources such as MassBank of North America, Global Natural Product Social Molecular Networking, PubChem, the US EPA CompTox Dashboard, NORMAN Database System, RforMassSpectrometry, and more. MassBank now boasts a total of 119 845 spectra of 18 529 compounds from 53 contributors from around the world.