Described is a technology in a programming (development and/or runtime) environment by which data type mismatches between the output and input of computer program software components (e.g., APIs) are detected, with the output transparently converted such that the converted input may be understood by the inputting component. When components are interconnected in a programming environment, metadata associated with those components is evaluated to determine a type mismatch, e.g., between objects and arrays. If mismatched, an output object is converted to a single-element array for input, or alternatively, an output array is converted to a series of objects, each object sent within a loop for input. The transparent conversion may be performed by the programming environment during runtime, or by inserting conversion code prior to compilation.