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ClassyFire is a web-based application for automated structural classification of chemical entities. This application uses a rule-based approach that relies on a comprehensible, comprehensive, and computable chemical taxonomy. ClassyFire provides a hierarchical chemical classification of chemical entities (mostly small molecules and short peptide sequences), as well as a structure-based textual description, based on a chemical taxonomy named ChemOnt, which covers 4825 chemical classes of organic and inorganic compounds. It can be accessed via the web interface or via the ClassyFire API.

ClassyFire is offered to the public as a freely acessible web server. Use and re-distribution of the data, in whole or in part, for commercial purposes requires explicit permission of the authors and explicit acknowledgment of the source material (ClassyFire) and the original publication (see below). We ask that users who download portions of the database, or use the service (via the server or the API), cite the ClassyFire paper in any resulting publications.


Please cite:

  1. Djoumbou Feunang Y, Eisner R, Knox C, Chepelev L, Hastings J, Owen G, Fahy E, Steinbeck C, Subramanian S, Bolton E, Greiner R, and Wishart DS. ClassyFire: Automated Chemical Classification With A Comprehensive, Computable Taxonomy. Journal of Cheminformatics, 2016, 8:61.
    DOI: 10.1186/s13321-016-0174-y

Chemical (Use this option when providing valid SMILES or InChIs as input)
Protein/DNA/RNA (Use this option when providing valid FASTA sequences as input)
IUPAC Name (Use this option when providing valid IUPAC names as input)

Provide one entry per line containing a SMILES or an InChI string, optionally preceded by an identifier. If added, the identifier MUST precede the structure representation. The line must be tab-separated.


Select a SDF or TSV file to upload. Maximum size: 3 MB.

Provide a name for the data sample. You can provide multiple tags separated by '|'.