MyChem.info provides simple-to-use REST web services to query/retrieve chemical and drug annotation data, aggregated from many popular data resources. It’s designed with simplicity and performance emphasized. You can use use it to annotate discovered chemical with the up-to-date chemical annotation; or query for specific known chemicals using a combination of your query criteria. MyChem.info can also be used to power a web application which requires querying or retrieving chemical annotations, without the need of maintaining your own local database backend.
The source code of MyChem.info project is currently hosted at github: https://github.com/biothings/mychem.info.