OPSIN converts IUPAC chemical names to SMILES, InChI and CML (Chemical Markup Language). Development started as part of Oscar3 before being developed further under the PhD of Daniel Lowe. It is available as a Java software library that may be used as a command-line application or included into other programs. It is also available via a web service that may be used for distributed applications or as a demonstration service (opsin.ch.cam.ac.uk).
OPSIN is licensed under the Artistic Licence 2.0 (http://www.opensource.org/licenses/artistic-license-2.0.php)