A multidisciplinary research team developed Fentanyl-Hunter, a machine learning-driven platform for comprehensive screening of fentanyl compounds and their metabolites in biological and environmental samples. The platform identified 27 previously unknown metabolites in vitro and detected opioid biomarkers across global samples, underscoring utility in forensic and toxicological contexts. Given the surge in fentanyl analog abuse contributing to tens of thousands of deaths annually, this rapid and accurate detection tool addresses critical challenges in monitoring synthetic opioids amidst evolving drug variants.