Information on TPs is provided by and available in several sources. One source is articles, which contribute a large part of the known transformation reactions. However, the reactions are often depicted in non-machine-readable formats, such as detailed reaction schemes depicted in figures, making them difficult and time-consuming to curate and make machine-readable. Another source of transformation reaction information is databases. Some examples include MetXBioDB and SWISSPEST19 as well as other NORMAN suspect lists (S66, S68 S74, S78, S79, and S81). All of these are combined within the PubChem Transformations library 12 together with transformation reactions from ChEMBL 13 , totalling 5 923 unique reactions by CID. The Rhea database also contains balanced transformation reactions of biological interest, with over 15 000 registered reactions. These databases can be used further, including as training sets for machine learning and as suspect lists for screening for TPs. However, the number of available reactions in all databases is low in comparison to the >350 000 compounds and mixtures registered for production and use on the global market, thus showing the need to expand these resources to include more of the known transformation reactions. Looking beyond reactions, several databases also contain text-based information about transformation reactions. Examples include PharmaGKB , DrugBank , the Toxin and Toxin Target Database and the Hazardous Substance Data Bank (HSDB) . Several of these data sources are included within the PubChem database. These datasets often facilitate finding metabolic information for specific compounds. However, finding information for large dataset purposes remains a time-consuming task.