- [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.
- [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.