- [Vert.X](http://vertx.io/) is a tool-kit for building reactive applications on the JVM.
- [Finagle](http://twitter.github.io/finagle) is an extensible RPC system for the JVM, used to construct high-concurrency servers.
- [Spring Boot](http://projects.spring.io/spring-boot/) makes it easy to create stand-alone, production-grade Spring based Applications that you can "just run".
- [Dropwizard](https://dropwizard.github.io/) is a Java framework for developing ops-friendly, high-performance, RESTful web services.
- [Spray](http://spray.io/) is an open-source toolkit for building REST/HTTP-based integration layers on top of Scala and Akka.
- [Kong](http://getkong.org/) is an open-source management layer for APIs.
- [Tyk](https://tyk.io/) is an open source, fast and scalable API gateway, portal and API management platform.
- [Camel](http://camel.apache.org/) empowers you to define routing and mediation rules in a variety of domain-specific languages, including a Java-based Fluent API, Spring or Blueprint XML Configuration files, and a Scala DSL.
- [Hazelcast](http://hazelcast.org/) is an open source in-memory data grid.
- [Galaxy](http://www.paralleluniverse.co/galaxy/) is an open-source high-performance in-memory data-grid.
### Resiliency
- [Simian Army](https://github.com/Netflix/SimianArmy) is a suite of tools for keeping your cloud operating in top form. Chaos Monkey, the first member, is a resiliency tool that helps ensure that your applications can tolerate random instance failures.
- [Hystrix](https://github.com/Netflix/Hystrix) is a latency and fault tolerance library designed to isolate points of access to remote systems, services and 3rd party libraries, stop cascading failure and enable resilience in complex distributed systems where failure is inevitable.
- [ZooKeeper](https://zookeeper.apache.org/) is an effort to develop and maintain an open-source server which enables highly reliable distributed coordination.
- [Etcd](https://github.com/coreos/etcd) a highly-available key-value store for shared configuration and service discovery.
- [Consul](https://consul.io/) Service discovery and configuration made easy. Distributed, highly available, and datacenter-aware.
- [Eureka](https://github.com/Netflix/eureka/wiki/Eureka-at-a-glance) is a REST based service that is primarily used in the AWS cloud for locating services for the purpose of load balancing and failover of middle-tier servers.