Synthetic biology aims to apply engineering principles in the designing of biological systems for a wide range of environmental, medical, and industrial applications. To be effective in these applications, the behavior of these systems must be tunable, precise, and robust over a range of conditions. Natural oscillators such as the circadian clock in cyanobacteria display remarkable precision in their period while being robust to environmental changes. While many synthetic genetic circuits have already been engineered to achieve various functions, many exhibit unreliable and unpredictable behaviors. In this project, we aim to engineer a precise genetic oscillator with tuneable and robust dynamics and to characterize the relationship between period, precision, and robustness in oscillatory gene networks. Using directed evolution we have generated large libraries of different circuit variants with the key parameters of the circuit mutated. A microfluidic device called the “mother machine” enables the screening of oscillatory dynamics of thousands of variants with single-cell resolution. Building such circuit libraries will lead to a deeper understanding of the design principles of natural oscillators, while providing biotechnological tools with potential applications, such as periodic drug delivery or engineered probiotics.