Looks like the Great Firewall or something like it is preventing you from completely loading www.skritter.com because it is hosted on Google App Engine, which is periodically blocked. Try instead our mirror:
This might also be caused by an internet filter, such as SafeEyes. If you have such a filter installed, try adding appspot.com to the list of allowed domains.
Skritter uses a custom built Spaced Repetition System. This endpoint allows you to access the user's custom SRS configuration based on their reviews and target retention rate. Use this data to build clients that can schedule Items the same as the official website and iOS client would.
Note: The values are continually updated based on reviews so a client that uses them should regularly refresh these entities.
Learn more about how to use these configuration objects in the scheduling documentation.