There are many products that qualify as a “in-memory data grid”, GemFire is one of the leading ones. From this article the main ones are:
VMware Gemfire (Java)
Oracle Coherence (Java)
Alachisoft NCache (.Net)
Gigaspaces XAP Elastic Caching Edition (Java)
Hazelcast (Java)
Scaleout StateServer (.Net)
Most of these products have drivers in many languages. You can access data in GemFire over REST, or over the native node.js client.
Apache Geode is the open source version of GemFire. It is much more powerful than memcached and Redis; You can use Geode not only as a cache, but as a store of record (it has native persistence). It has an Object Query Language (OQL) engine built in, which allows you to query nested objects, has powerful features like Continuous Queries and replication over WAN, among others. Geode also has protocol adapters for memcached and Redis, allowing your memcached and Redis clients to connect to Geode.