RxJS

Akka is a toolkit and runtime for building highly concurrent, distributed, and resilient message-driven applications on the JVM.

Netty is a NIO client server framework which enables quick and easy development of network applications such as protocol servers and clients. It greatly simplifies and streamlines network programming such as TCP and UDP socket server.

It is an open source library providing an asynchronous, event driven platform for building fast, reliable, and lightweight network applications. It leverages Rust's ownership and concurrency model to ensure thread safety.

It allows developers to dispatch a function that returns an observable, promise or iterable of action(s). Compose and cancel async actions to create side effects and more.

Finagle is an extensible RPC system for the JVM, used to construct high-concurrency servers. Finagle implements uniform client and server APIs for several protocols, and is designed for high performance and concurrency.

Orleans is a framework that provides a straightforward approach to building distributed high-scale computing applications, without the need to learn and apply complex concurrency or other scaling patterns. It was created by Microsoft Research and designed for use in the cloud.

It is a type-safe composable asynchronous and concurrent programming library for Scala that is based on pure functional programming.

It is a Next generation Actor Model framework. It introduces "Actor Standard Protocol", a predefined contract of base primitives which can be consumed by different language implementations. This is a game changer in the field of actor systems, you are now free to pick and choose languages for your different actor based microservices in a way never seen before.

It is your toolbelt for structured concurrency in go, making common tasks easier and safer. It handles panics gracefully and makes concurrent code easier to read.

It is an open-source concurrency/parallelism library for Java and Groovy that gives you a number of high-level abstractions to write good logic.

Scramjet is a fast, simple, free and open source functional reactive stream programming framework written on top of node.js streams with multi-threadding support. The code is written by chaining functions that transform data easily with ES7 async/await syntax. It is built upon the logic behind three well known javascript array operations: map, filter and reduce. Scramjet transforms are so standard and natural that we're sure you can start writing your code straight away.

It manages synchronous and asynchronous code easily, using nothing more than standard JavaScript and Node-like Streams. You may be familiar with Promises, EventEmitters and callbacks, but moving between them is far from seamless.