22Increasing availability of comprehensive experimental datasets and of high-performance 23 computing resources are driving rapid growth in scale, complexity, and biological realism of 24 computational models in neuroscience. To support construction and simulation, as well as 25 sharing of such large-scale models, a broadly applicable, flexible, and high-performance data 26 format is necessary. To address this need, we have developed the Scalable Open Network 27 Architecture TemplAte (SONATA) data format. It is designed for memory and computational 28 efficiency and works across multiple platforms. The format represents neuronal circuits and 29 simulation inputs and outputs via standardized files and provides much flexibility for adding new 30 conventions or extensions. SONATA is used in multiple modeling and visualization tools, and 31 we also provide reference Application Programming Interfaces and model examples to catalyze 32 further adoption. SONATA format is free and open for the community to use and build upon 33 with the goal of enabling efficient model building, sharing, and reproducibility.34 68 compute environments. Another is that existing formats describe either static models or 69 simulation outputs, but not both. And, for broad adoption of a modeling data format, it needs to 70 be flexible enough to represent a variety of model types (point neuron, biophysically detailed, 71 etc.) and compatible with more specialized formats (e.g., SWC for neuronal morphologies 72 (Cannon et al., 1998)), without compromising computational performance. 73 3 74