This paper describes the detection of endogenous cyanide using corrin-based CyanoKit technologies in combination with a smartphone readout device. When applied to the detection of cyanide in water, this method demonstrates high repeatability and discriminative power with a limit of blank of 0.074 ppm and an instrument limit of detection of 0.13 ppm. Quantification of endogenous cyanide in cassava and bitter almond extracts with the smartphone readout is in excellent agreement with independent analyses using traditional spectrophotometric detection. The prototype system objectively detects levels of cyanide with a high granularity at the point-of-need and does not depend on large, heavy and expensive instrumentation. The methodology has the potential to be easily adopted in resource limited situations and low-income countries.