At Rearc, we work with hundreds of datasets sourced directly from various authorities, government agencies, and organizations. A core part of the value we provide to our customers is ensuring that they receive clean and reliable data, no matter what the raw original data looks like. While some of this is accomplished by enforcing data types and strict schemas, errors can easily slip through the cracks. To address these problems, we began investigating solutions for a succinct, self-documenting, self-verifying way of declaring what the output data should look like.