timestamped JSON objects.
OBJ is a package that provides an object class that can save/load objects in JSON format to disk, thus providing persistence to objects. Files are saved with a timestamp in their filename, so that searching in a time related manner becomes possible. Modules are provided to query saved objects as well as to run objects with a thread to manage their state. The directory that is used to save the objects is configurable in the obj package, use cfg.workdir.
OBJ has a “no-clause MIT license” that should be the most liberal license you can get at the year 2018.