FaaSCache, is a transparent, vertically and hori- zontally elastic in-memory caching system for Function as a Service platforms. The cache is distributed over the worker nodes to mitigate the overheads of frequent interactions with an external data store, as required by the stateless FaaS paradigm. FaaSCache prototype based on enhancements to the Apache OpenWhisk FaaS platform, the OpenStack Swift persistent object storage service, and the RAMCloud in-memory store.