Zinc Database

Gives you programmatic access to ZINC's 230+ million purchasable compounds through the CartBlanche22 API. You can search by ZINC ID, run similarity searches with SMILES strings and distance thresholds, pull random compound sets filtered by drug-like or lead-like properties, and grab supplier codes for ordering. The tranche system encodes molecular properties directly in the identifier (H-bond donors, LogP, molecular weight), which is handy for quick filtering. Most useful when you're building docking libraries, hunting for analogs of a hit compound, or need to verify what's actually commercially available before you waste time on virtual screening. The API returns tab-delimited text or JSON, so it's straightforward to pipe into your existing cheminformatics workflow.