Chembl Database

This gives you direct access to ChEMBL's 2+ million bioactive compounds and 19 million activity measurements through Python. You can search by molecular structure, filter by properties like IC50 or Ki values, find inhibitors for specific targets, and pull drug mechanism data. It's built on the chembl_webresource_client and supports Django-style filters for complex queries. Really useful if you're doing medicinal chemistry work, SAR studies, or drug repurposing research and need to quickly grab compound-target interaction data without writing your own EBI API wrapper. The caching is sensible and it handles pagination automatically, so you can iterate through large result sets without thinking about it.