TurKit is a toolkit for building human computation algorithms. It allows researchers to integrate human input into algorithms through tasks on Amazon Mechanical Turk. The document describes two example systems (VizWiz and Soylent) that use TurKit and human computation to provide services: VizWiz helps blind users get descriptions of visual scenes, while Soylent integrates crowd workers directly into Microsoft Word for tasks like proofreading. TurKit provides tools for designing iterative and parallel human computation workflows.