Azure Cosmos DB vs FoundationDB

Azure Cosmos DB is a globally distributed, multi-model database service by Microsoft offering single-digit millisecond latency and 99.999% availability SLA. It supports document, key-value, graph, and column-family data models with multiple API options.

FoundationDB is a databases tool that distributed key-value store from apple providing acid transactions across a scalable, fault-tolerant cluster. It is open source software.