Amazon MemoryDB vs. Amazon Aurora

Amazon MemoryDB for Redis is a Redis-compatible, durable, in-memory database that delivers ultra-fast performance and Multi-AZ durability. With Amazon MemoryDB for Redis, you only pay for what you use with no minimum fee. A node is the smallest building block of a MemoryDB cluster. Each node supports varying amounts of computation and memory capacity, and you can select a node type based on your needs. You are charged based on three components: on-demand instance hours per node, volume of data written to your cluster, and snapshot storage that you use.

Amazon Aurora is a fully managed relational database service that combines the performance and availability of high-end commercial databases with the simplicity and cost-effectiveness of open-source databases. Compatible with MySQL and PostgreSQL, Aurora delivers up to five times the throughput of standard MySQL databases and up to three times that of standard PostgreSQL databases. It is designed for high availability, offering up to 99.99% availability within a single region and up to 99.999% across multiple regions.