Open-source alternatives to Libevent

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

Muduo is a C++11 event-driven network library and framework designed for building high-concurrency Linux servers. It provides a toolkit for implementing scalable network services and socket communication using non-blocking I/O and asynchronous event processing. The framework implements a multi-threaded TCP server architecture that distributes connection handling across multiple CPU threads to maximize server throughput. This is achieved through a one-loop-per-thread model and a reactor pattern implementation, which dispatch network events from a central demultiplexer to registered handler fun

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

Flecs is a high-performance entity component system framework and data-oriented programming library. It serves as a simulation engine core and game engine architecture tool, decoupling state from behavior by separating entities, components, and systems. The framework features a runtime reflection layer for dynamic data inspection and a built-in scripting system for defining entity behavior without recompilation. It also includes a network interface and REST API for remote simulation administration and state querying. The library covers a broad surface of simulation capabilities, including ar

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

This project is a curated educational guide and instructional resource for the Node.js runtime environment. It serves as a comprehensive introduction to core concepts, including asynchronous programming tutorials, network application primers, and guides on the module system and stream API. The material focuses on the fundamental building blocks of server-side development, specifically how to create reusable code packages and manage project dependencies via a module manifest. It provides detailed instruction on building programs that communicate over HTTP and TCP protocols to exchange data acr

Drogon is a high-performance, cross-platform C++ framework designed for building asynchronous web services and server-side applications. It functions as a multi-threaded, event-driven server engine that manages concurrent network traffic and WebSocket connections with minimal latency. By leveraging non-blocking input/output and native code compilation, the framework provides a foundation for scalable applications that operate efficiently across diverse hardware architectures. The framework distinguishes itself through its compile-time template rendering, which transforms dynamic HTML views in

uvloop is a high-performance replacement for the standard Python event loop. It functions as a drop-in substitute designed to accelerate asynchronous networking tasks and reduce latency in event-driven software systems. The project achieves its performance characteristics by utilizing a Cython-based extension module that wraps the libuv C library. By leveraging low-level system calls for event-driven input and output multiplexing, it manages concurrent network requests and subprocess execution with minimal overhead. The implementation supports scalable backend service development by handling

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

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

This project is a comprehensive, curated directory of high-quality libraries, tools, and educational resources for C and C++ development. It serves as an ecosystem discovery index, helping developers navigate the vast landscape of third-party components, frameworks, and technical documentation available for the language. The collection is distinguished by its focus on high-performance systems programming and technical mastery. It provides deep coverage of specialized domains including SIMD-accelerated data processing, compile-time template metaprogramming, and asynchronous event-driven archit

qBittorrent is a cross-platform desktop application designed for peer-to-peer file distribution. It functions as a BitTorrent client that manages the downloading and uploading of files across decentralized networks by utilizing a high-performance C++ library to handle protocol compliance and data exchange. The application distinguishes itself through an integrated, asynchronous event-driven architecture that supports remote management via an embedded web server. This remote interface allows users to control tasks and application settings from any location, secured by authentication, encryptio

llrt is a low-latency JavaScript runtime based on the QuickJS engine, specifically designed for executing asynchronous functions in serverless environments. It provides a lightweight execution layer optimized for fast startup times and minimal memory usage when running ES2023 workloads. The project differentiates itself by bundling natively optimized cloud service SDKs directly into the runtime binary to eliminate external dependency loading. To further reduce cold start latency, it implements parallel connection warming for TLS and network handshakes during the startup phase. The runtime co

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

This is a header-only C++ library that provides implementations for HTTP clients, HTTP servers, and a WebSocket framework. It allows for the creation of network services and the consumption of remote APIs without requiring a separate compilation step or external binary linking. The project features backend-agnostic TLS integration for secure HTTPS and WSS communication and employs a thread-pool model to process concurrent requests. It distinguishes itself with a full-duplex WebSocket state-machine and a middleware-based request pipeline that supports regular-expression path routing. The libr

Python is a high-level, interpreted programming language designed for readability and versatility. It operates via a bytecode-based virtual machine and manages memory automatically through reference-counting garbage collection. The language supports multiple programming paradigms, including object-oriented, imperative, and functional styles, and provides a comprehensive standard library for system operations, networking, and data handling. The language is distinguished by its dynamic nature, allowing for runtime object introspection and metaclass-driven class creation. It utilizes protocol-ba

This project provides a server-side language runtime and a standardized Docker image for deploying applications across different operating systems. It functions as an execution environment for generating dynamic HTML, JSON, and XML content, while also serving as a command line interface for automation scripts and background jobs. The runtime is designed for extensibility through a C-based extension architecture, allowing the loading of custom modules for specialized functionality. It supports multiple server application interfaces, including a FastCGI web interface for high-performance commun

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

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 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

The C++ REST SDK is a library for asynchronous HTTP and RESTful communication in native C++ applications. It provides a non-blocking network client for sending requests and receiving responses, a JSON parser for serializing and deserializing data, and a WebSocket client library for real-time, full-duplex communication. The project includes a dedicated OAuth2 authentication client to manage access tokens and authorization flows for secure communication with protected cloud resources. It utilizes a task-based asynchronous model to coordinate background operations and keep application interfaces

Vert.x is a reactive polyglot framework and asynchronous programming library for the Java Virtual Machine. It functions as an event-driven networking framework and toolkit for building non-blocking applications. The system enables the development of high-concurrency network services and event-driven microservices. It supports the creation of reactive services using multiple languages running on the JVM. The framework covers a wide range of capabilities including the management of HTTP and TCP network protocols, non-blocking file system access, and the integration of reactive clients.

Sanic is an asynchronous Python web framework designed for building high-performance APIs and services. It operates as a production-ready ASGI web server, utilizing a non-blocking event loop to handle concurrent requests and maximize throughput. The framework is built to support scalable architectures, offering built-in worker process management to distribute traffic across available CPU cores. What distinguishes Sanic is its focus on modularity and developer-centric tooling. It features a blueprint-based system for organizing complex applications into pluggable components, alongside a robust

fsnotify is a cross-platform filesystem notification library that provides a programming interface for tracking file and directory changes within Go applications. It utilizes native kernel notification interfaces to detect events such as file creation, deletion, and attribute updates, allowing developers to integrate real-time monitoring into their software. The library distinguishes itself by providing a unified abstraction layer that normalizes disparate kernel APIs into a consistent event stream. It manages high-volume activity through non-blocking event polling and internal memory bufferi

Swifter is a lightweight HTTP server engine and networking library for the Swift programming language. It provides a minimal networking layer designed for hosting internal web services, building server-side applications, and implementing custom HTTP servers. The project enables the creation of embedded web services for remote control or status monitoring and supports lightweight web hosting with a minimal footprint. Its capabilities cover the management of raw TCP connections and network sockets, using a request-response cycle to parse incoming data into HTTP requests and map them to handler

CocoaHTTPServer is a lightweight embedded web server designed to handle incoming network requests and serve local application content. The project implements Bonjour-based service discovery to broadcast server availability on local networks and supports WebDAV for remote file management, allowing files to be created, moved, and edited over HTTP. Network security is handled through certificate-based TLS encryption and password-based resource authentication. Request routing is managed via a delegate-based system, while concurrent connections are handled using Grand Central Dispatch.

NanoHTTPD is a lightweight, embeddable HTTP server for Java applications. It allows developers to integrate web server capabilities directly into a Java project to handle incoming requests without requiring a standalone installation. The project provides specialized implementations for an HTTPS web server, a WebSocket server for bidirectional real-time communication, and a static file web server. These capabilities enable secure network traffic through SSL certificates and the delivery of local files with automatic MIME type detection. The server includes systems for request routing and hand