One of the Clojure validation libs predating spec, schema, has saved us from a ton of errors, and works similarly. It also opens up reasoning about data shape-

One of the Clojure validation libs predating spec, schema, has saved us from a ton of errors, and works similarly. It also opens up reasoning about data shape- eg, auto-generating test data based on schemas. spec's support for that use case is even better. EDIT: You can see schema in action in https://github.com/cardforcoin/shale https://github.com/cardforcoin/shale. In fact, the latest build surfaced a bug via schema- https://circleci.com/gh/cardforcoin/shale/379 https://circleci.com/gh/cardforcoin/shale/379. Next version we're planning to migrate to spec.