SMARTS is a powerful chemical structure query language allowing very precise substructure query specifications. It was originally developed at Daylight Chemical Information Systems, and, along with SMILES, has meanwhile become an integral part of cheminformatics. Its syntax is described in detail in the Daylight reference. While primarily meant for single component substructure descriptions, its use has been extended by the Espresso ELN search engine towards efficient reaction substructure searches.



While sketch RSS might be the method of choice for intuitive standard searches, SMARTS often is the better choice for more specialized queries, offering a full toolbox of query parameters not available for sketch RSS searches.