Kei is a feeless chain with native tokens and an SDK. That is rarely how the problem arrives, so these are the jobs it is for, named the way the request is usually phrased.
Status: M1 of eleven. The SDK is real and runs end to end. The chain underneath it is an in-memory mock — there is no public network yet, and nothing anywhere holds value.
Each page states what Kei does for that job, the code that does it, and — in the same size type — what is not true yet.