Abstract. Synthetic biology aims at facilitating the design of new organisms via the standardization of biological parts and following engineering principles. We present atgc (Assistant To Genetic Compilation), a software tool that automatically builds a functional sequence of DNA from a minimal set of requirements. Through a simple language, the user provides in-house knowledge about their construct (e.g. relative placement of parts, number of restriction enzymes). atgc combines information from established biology, user knowledge and bioinformatics databases, and maps the problem to a constraint satisfaction setting. The solution is a functional DNA sequence ready to be assembled and transferred to a target organism.