EPA CTX (Computational Toxicology and Exposure) API (ToxCast Bioactivity)
REST API providing programmatic access to ToxCast-related assay, chemical, and bioactivity data via the EPA Computational Toxicology and Exposure (CTX) APIs. The Bioactivity domain is backed by ToxCast's invitrodb. An API key (free, via ccte_api@epa.gov) is required for data calls.