Open-source alternatives to Eventmachine

Twisted is an event-driven networking engine for Python that provides a framework for building asynchronous network applications. At its core, it uses a reactor-based event loop to drive all input and output, dispatching callbacks in a single thread without blocking. The library implements a deferred promise chain for composing asynchronous logic, along with a protocol and factory pattern that separates connection state management from protocol handling, enabling reusable handlers for different network protocols. The framework supports multiple event loops across platforms, including select,

Swoole is a coroutine-based concurrency library and IO framework for PHP. It provides a system for building high-performance network servers and applications by bringing asynchronous, event-driven, and coroutine-based concurrency to the PHP runtime. The project distinguishes itself by implementing user-space coroutine scheduling and non-blocking IO interception, which transforms standard blocking network and file operations into asynchronous actions. It further enables high-speed data exchange across multiple PHP processes through shared memory management and specialized data structures. The

CppGuide is a curated collection of educational resources and practical guides focused on C++ server development, Linux kernel internals, concurrent programming, network protocols, and security exploitation. It provides structured learning paths for backend developers, covering everything from interview preparation to building high-performance network servers and understanding operating system fundamentals. The guide distinguishes itself by offering in-depth, hands-on tutorials that walk through real-world implementations, including building a Redis-like server from scratch, designing custom

Message-io is an event-driven networking library written in Rust that provides a unified message-based API for building applications across multiple transport protocols. It allows developers to handle communication over TCP streams, UDP datagrams, and WebSocket connections through a single interface, while managing underlying network connections, message transport, and low-level socket asynchrony. The library utilizes a single-threaded event loop architecture to process incoming connections, disconnections, network messages, and internal signals on a dedicated thread, eliminating traditional

This project is a detailed analysis and study of the Nginx source code, focusing on high-performance server architecture and function call flows. It serves as a technical examination of the internal C implementation used to build high-concurrency networking systems. The project deconstructs the internal mechanisms of the web server, including the multi-process master-worker model, event-driven asynchronous I/O, and non-blocking socket communication. It analyzes the phase-based request processing lifecycle, from URI matching and header parsing to final content generation. The study covers a b

DotNetty is an asynchronous network framework and event-driven networking library for .NET. It is a port of the Netty architecture designed for building high-performance protocol servers and clients. The framework enables the development of network applications that handle concurrent connections and high-throughput data streaming without blocking execution threads. It supports the implementation of custom network protocols through defined encoding and decoding rules. The library utilizes a pipeline-based processing model and non-blocking I/O to manage network traffic. Its architecture incorp

ReactPHP is an asynchronous runtime and event-driven I/O framework for PHP. It provides an environment for executing concurrent tasks through a central event loop implementation and reactor pattern, allowing applications to handle multiple operations without pausing the main execution thread. The project includes a specialized asynchronous socket library for TCP, UDP, and TLS communication, alongside a non-blocking HTTP server and client for streaming web requests and responses. Its capability surface covers asynchronous control flow via promises and fibers, non-blocking network connectivity

This project is a read-only archive of historical versions and development records for an early V8-based JavaScript runtime. It functions as an event-driven server-side environment that executes JavaScript code outside of a web browser. The archive preserves the identity of the runtime as an evented I/O framework, designed for handling asynchronous network and file system operations through a non-blocking event loop. It provides access to read-only records of old issues and pull requests to track the evolution of these legacy versions. The project covers the domain of server-side execution a

Mio is a low-level I/O library for Rust that provides an event-driven framework for monitoring multiple network sockets and file descriptors. It acts as a portable wrapper for operating system native polling systems, including epoll, kqueue, and IOCP, allowing applications to trigger events when resources are ready for reading or writing without blocking the execution thread. The library provides a non-blocking socket interface for managing TCP, UDP, and Unix sockets. It distinguishes itself through a vectored I/O implementation, enabling scatter-gather reads and writes across multiple buffer

libuv is a cross-platform asynchronous I/O library that provides an abstraction layer for event-driven networking, filesystem operations, and system signals. It utilizes a non-blocking event loop to coordinate asynchronous tasks and I/O events across different operating systems. The project features a unified interface for managing TCP, UDP, and DNS resolution, alongside an inter-process communication layer for sharing sockets via named pipes and Unix domain sockets. To prevent blocking the main execution loop, it includes a multi-platform thread pool for offloading computationally expensive

Boost is a collection of portable, high-performance source libraries that extend the C++ standard library. It provides a wide range of reusable components, data structures, and algorithms designed to add capabilities to the base language across different platforms. The project is distinguished by its extensive focus on compile-time template metaprogramming and generic programming. It implements advanced architectural patterns such as policy-based design, concept-based type validation, and the use of SFINAE for conditional template resolution to minimize runtime overhead. The library covers a

This project is a framework for building concurrent, event-driven applications in Ruby. It provides a core engine that orchestrates non-blocking input and output operations, allowing developers to handle high-volume network traffic and system tasks without the complexity of traditional callback-based programming. By leveraging lightweight fibers, the library enables cooperative multitasking that maintains responsiveness during heavy data processing workloads. The framework distinguishes itself through a structured concurrency model that organizes tasks into parent-child hierarchies. This appr

Netpoll is an event-driven network framework and non-blocking I/O library designed to manage concurrent TCP and Unix domain socket connections. It utilizes a non-blocking event loop to monitor file descriptors and trigger callbacks for read and write events, serving as a high-performance socket manager and TCP network poller. The framework optimizes throughput across CPU cores by distributing incoming network connections across multiple pollers. It implements zero-copy networking primitives, using linked buffers and specialized memory management to read and write data while minimizing memory

An asynchronous I/O and reactor event loop library for PHP, this project provides core primitives for coordinating non-blocking operations, managing system resources, and scheduling background tasks. The runtime executes concurrent operations by continuously running tick-based loop iterations that process pending timers, network streams, deferred callbacks, and system signals through efficient system-level polling mechanisms. The library coordinates event-driven execution using asynchronous timers for one-off or periodic tasks, next-tick deferred execution for breaking down workloads, and str

HP-Socket is a networking library for building scalable TCP, UDP, and HTTP servers and clients with event-driven I/O and SSL encryption. It provides a high-performance TCP server framework, an HTTP request handler that parses incoming requests and generates responses, and a UDP communication library for low-latency data transfer, all with optional SSL encryption for secure communication. The library is built on a completion-port-based I/O architecture that uses Windows I/O Completion Ports for scalable asynchronous socket operations. It features a connection-pooled agent architecture for mana

async-std is a Rust asynchronous runtime and non-blocking I/O library. It serves as an asynchronous standard library, providing a set of alternatives to the core Rust library for managing concurrent tasks, networking, and file system access. The project implements a standard-library-mirrored API, offering asynchronous versions of existing synchronous types to maintain a familiar interface. This approach allows for asynchronous Rust development using an interface that reflects the ergonomics of the language's standard library. The runtime includes a task executor for scheduling and executing

evpp is a C++ network library and framework designed for building high-performance network services using TCP, UDP, and HTTP protocols. It provides an asynchronous event loop to manage nonblocking I/O operations and concurrent network connections across multiple threads. The framework includes specialized tools for asynchronous DNS resolution and a system for asynchronous task scheduling using a managed thread pool. It also features a nonblocking HTTP server and client with integrated connection pooling. The project covers low-level transport layer connectivity for TCP and UDP, as well as hi

TCP-IP-NetworkNote is a comprehensive technical reference and guide for implementing network communication using TCP and UDP sockets in C and C++. It provides a detailed manual for using the POSIX socket API and covers the implementation of network protocols, synchronous and asynchronous I/O patterns, and concurrent programming models. The project is distinguished by its focus on cross-platform networking, offering a detailed comparison of socket implementation details and adaptation utilities between Linux and Windows Winsock environments. It specifically addresses the differences in header

f-stack is a kernel-bypass framework and user-space TCP/IP stack designed to increase packet processing speeds and overall throughput. It utilizes DPDK to route network traffic directly to user space and integrates a transplanted FreeBSD network stack to handle transport and network layer protocols outside of the host operating system. The project provides a socket API compatibility layer that allows standard network applications to run on a high-performance backend without requiring code changes. It also features a coroutine-based network API and micro-threading interface to manage asynchron

Node.js is an open-source, cross-platform JavaScript runtime environment built on the V8 engine, designed for executing JavaScript code outside a web browser. It operates as a server-side JavaScript platform with an event-driven, non-blocking I/O architecture that enables building scalable network applications and web servers. The runtime integrates the CommonJS module system for synchronous module loading and the npm ecosystem for sharing and reusing packages. The platform provides comprehensive capabilities for web server development, including creating HTTP and HTTPS servers, managing HTTP

Trio is an asynchronous I/O runtime and concurrency library for Python. It provides a system for executing non-blocking network and disk operations through a centralized event loop and task scheduler. The library is built on a structured concurrency model, which ensures that asynchronous tasks are bound to a specific lifetime and cannot outlive the scope that started them. It utilizes a nursery-based task manager to track task lifecycles in a parent-child tree, preventing orphaned concurrent operations by requiring child tasks to be joined before their parent scope exits. The framework cover

Smol is a lightweight Rust asynchronous runtime and task executor. It provides a suite of foundational tools for scheduling and executing asynchronous futures, managing background workloads, and handling non-blocking network and file operations. The project includes a compatibility layer for adapting asynchronous types and execution contexts, enabling futures to run across different runtime ecosystems. It also features a mechanism to offload synchronous I/O and CPU-intensive operations to dedicated worker thread pools to prevent runtime stalls. Its capabilities cover non-blocking network I/O

EasySwoole is a high-performance asynchronous PHP framework designed for building event-driven networks and persistent memory applications. It functions as a toolkit for developing distributed microservices and asynchronous servers capable of handling concurrent HTTP, TCP, UDP, and WebSocket connections. The framework distinguishes itself through a persistent memory process execution mode that eliminates the overhead of repetitive file loading and invocation during request handling. It provides built-in support for distributed systems via remote procedure call implementations and service disc

cppcoro is a C++ coroutine library and concurrency toolkit providing primitives for asynchronous tasks, lazy generators, and non-blocking execution. It functions as an asynchronous I/O framework for managing network sockets and file operations through an event loop. The library features a work-stealing thread pool for distributing tasks across multiple cores and a set of async generators for producing lazy sequences of values both synchronously and asynchronously. It includes a concurrency toolkit with async mutexes, latches, and shared tasks to coordinate multi-threaded execution. Its capab

This library provides a framework for building event-driven, non-blocking network applications in PHP. It enables the development of asynchronous TCP and TLS servers and clients that manage multiple concurrent connections without stalling the main execution thread. By utilizing an event-loop architecture, the library handles network operations and data exchange through asynchronous streams, ensuring that the application remains responsive during high-throughput tasks. The project distinguishes itself through its integration with operating system primitives, such as raw file descriptors and Un

libhv is a high-performance C/C++ network library and event-driven I/O framework used to build TCP, UDP, SSL, HTTP, WebSocket, and MQTT clients and servers. It provides a non-blocking event loop for managing network sockets, timers, and system signals across multiple threads. The project is distinguished by its integrated support for specialized network roles, including a full HTTP web server with RESTful routing and middleware, an MQTT messaging client for IoT communication, and the ability to implement SOCKS5 and HTTP proxies. It also features a reliable UDP implementation to ensure ordered

SuperSocket is a .NET socket server framework designed for building network servers and custom communication protocols. It functions as a pipeline-based network engine and a server for TCP, UDP, and WebSocket protocols. The framework provides a socket session manager to track and control the lifecycle of network connections and client request states. It enables the implementation of bespoke communication standards and the development of socket proxies. The system handles concurrent client connections and processes network traffic through a structured architecture of pipeline filters, middlew