"I've been personally frustrated by teammates using external key/value stores for hot data sets which would trivially fit within RAM. But haven't had ready-made

"I've been personally frustrated by teammates using external key/value stores for hot data sets which would trivially fit within RAM. But haven't had ready-made solutions." You don't need a ready made solution unless you are trying to keep the data consistent, too. If you are, better to use something off the shelf. If you aren't...just deserialize it into whatever local data format makes sense, the same as you'd do reading from an external cache. You basically just have some push/poll mechanism to get data from your data store when updated/at intervals, deserialize it, and now it lives in RAM. The one downside of that is if autoscaling is thrashing instances, it can thrash your data store (though that's true with Redis etc too, depending what is loading data into it; having a caching layer in between DOES decouple that), and also what happens if the data store is unreachable (I've done things like query the rest of the cluster for the data, just via a REST API, because the total amount needed was all of a few megs).