Open-source alternatives to Paho.mqtt.c

This library is an Arduino-compatible client for the messaging protocol designed for resource-constrained embedded systems. It provides a messaging interface that enables microcontrollers to establish persistent connections with brokers to exchange data and control signals. The library distinguishes itself through a focus on predictable resource usage, utilizing manual memory buffer management and a state-machine approach to handle connection persistence and automatic reconnections. It operates on a stream-oriented network abstraction, allowing it to interface with various hardware transport

This project is the official documentation site and communication standard portal for the MQTT messaging protocol. It serves as a central hub for technical specifications and implementation guidelines designed for lightweight messaging in internet-of-things environments. The site is implemented as a static website, utilizing static site generation and markdown-based content authoring to distribute protocol specifications and technical standards. The resources cover a broad range of industrial messaging and connectivity capabilities, including publish-subscribe routing, quality-of-service del

MQTTnet is a comprehensive MQTT library for .NET that supports both client and broker roles in a single codebase. It provides a full-featured broker implementation capable of hosting a server with access control, message interception, session persistence, and support for mixed MQTT protocol versions. The client side offers robust publish-subscribe communication with automatic reconnection that preserves quality-of-service guarantees, ensuring reliable message delivery across network interruptions. The library distinguishes itself with a plugin-based authentication pipeline for validating clie

This project provides a technical specification and reference manual for the MQTT 3.1.1 standard, serving as a translated Chinese guide for implementing this lightweight IoT messaging protocol in resource-constrained device networks. The documentation covers the fundamental mechanisms of the publish-subscribe model, including topic-based routing with wildcard filtering, retained message storage, and the configuration of last will and testament messages. It details the protocol's approach to reliability through various quality of service levels, ranging from single-level acknowledgments to exa

This project is a lightweight MQTT client library for Arduino boards, specifically designed for embedded systems utilizing an Ethernet Shield. It functions as an embedded messaging client that allows hardware devices to publish and subscribe to topics on a remote message broker. The library provides core MQTT integration, including broker connection management and the maintenance of server heartbeats. It supports topic-based message publishing and subscription management, enabling the registration of listeners to trigger functions upon message arrival. The system covers network connection co

libwebsockets is an event-driven networking framework written in C. It provides a suite of tools for implementing HTTP servers and clients, WebSocket bidirectional communication, MQTT client messaging, and TLS-enabled socket encryption. The project distinguishes itself through a non-blocking event-loop architecture capable of scaling to high connection volumes by distributing network sessions across multiple service threads. It uses a protocol-based callback system and a pluggable event loop integration that allows the networking core to synchronize with external system event libraries. The

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

This project is a comprehensive computer networking textbook and instructional resource. It serves as a technical guide for the design and implementation of network layers, protocols, and hardware architecture, covering the spectrum from physical links to application-layer protocols. The content provides a detailed study of standards for congestion control, reliable data delivery, and internetwork routing. It includes specialized technical material on network security, public-key infrastructure, and the operation of modern cloud infrastructure and data centers. The material covers a broad ra

uWebSockets is a C++ networking framework that serves as a high-performance WebSocket server library, HTTP web server, and pub-sub messaging system. It provides the infrastructure necessary to handle standard web requests and maintain low-latency, bidirectional connections between clients and servers. The framework is distinguished by its use of template meta-programming for compile-time optimization and zero-copy buffer management to minimize memory latency. It utilizes a backend-agnostic event loop and static route resolution to process network traffic with minimal runtime overhead. The pr

This is a header-only C++ library and asynchronous network framework used to implement WebSocket clients and servers. It provides a full implementation of the WebSocket protocol, including handshakes, subprotocol negotiation, and frame parsing. The framework is distinguished by a policy-based transport layer and template-driven protocol negotiation, allowing the underlying network implementation to be swapped between raw buffers, streams, or custom policies. It supports per-message deflate compression to reduce data transmission volume and integrates Transport Layer Security for encrypted bid

Beast is a C++ library for implementing low-level HTTP and WebSocket clients and servers. It functions as an asynchronous networking framework designed to compose non-blocking I/O operations and layered stream stacks for managing concurrent network traffic, specifically utilizing the Boost.Asio asynchronous model. The library provides a comprehensive implementation of the HTTP/1.1 and WebSocket protocols. For HTTP, it includes primitives for parsing and serializing messages with support for chunked transfer encoding, incremental body reading, and request pipelining. Its WebSocket implementati

Netty is an asynchronous network framework designed for building scalable protocol servers and clients. It utilizes an event-driven reactor pattern and a non-blocking input/output model to decouple connection handling from application logic, allowing for the development of responsive network services that manage high volumes of concurrent connections. The framework distinguishes itself through a modular pipeline-based processing chain that enables the implementation of custom binary or text-based protocols. It provides a pluggable transport abstraction that allows developers to switch between

websockets is a Python library for building WebSocket servers and clients using coroutines and the asyncio framework. It provides a complete toolkit for creating production-ready WebSocket applications, including a coroutine-based framework for handling connections, messages, and lifecycle events, as well as a client library for opening persistent bidirectional connections to remote endpoints. The library manages the full lifecycle of WebSocket connections, including handshake, message exchange, and graceful closure, with support for path-based routing to organize server logic across multiple

MQTTX is a cross-platform MQTT client application designed for testing, debugging, and managing MQTT brokers. It supports both MQTT v3.1.1 and v5.0, enables simultaneous management of multiple broker connections, and provides an interactive chat-style interface for publishing and subscribing with configurable quality of service, payload transformation, and topic visualization. The client can be used as a desktop application, a command-line tool, or a self-hosted web client deployable via Docker. What sets MQTTX apart is its integration of AI-assisted workflows, allowing users to generate MQTT

MQTTnet is a .NET library providing a framework for implementing MQTT clients and brokers. It includes a broker implementation for hosting a central message hub that routes messages between connected clients and a client library for publishing and subscribing to messages. The project supports both TCP and WebSocket transport layers, enabling secure data traffic through transport layer security. It allows for the development of custom middleware to intercept, transform, or validate messages as they pass through a server. Capability areas include distributed message routing, persistent connect

Mpush is a real-time message push system and encrypted messaging gateway designed to deliver instant notifications to mobile and web clients. It functions as a session management service and a network traffic controller, utilizing persistent network connections to ensure updates reach users without manual screen refreshing. The system includes an HTTP reverse proxy that routes external domain requests to internal IP addresses with integrated connection timeout management. It maintains communication stability through a persistent session manager that tracks client heartbeats and session expira

This is a Go client library and protocol implementation for interacting with message brokers using the AMQP 0.9.1 standard. It serves as an asynchronous messaging toolkit and message queue client for implementing producer and consumer patterns. The library provides a programmatic interface for managing the full message lifecycle, including publishing, consumption, and delivery acknowledgments. It supports reliable delivery mechanisms such as publishing confirmations and atomic transactions. The project covers the administration of routing topologies through the declaration and binding of que

Hiredis is a minimalistic C client library designed to send commands and receive responses from Redis servers using a binary-safe protocol. It functions as a core toolkit providing a Redis protocol parser, a secure connector, and both synchronous and asynchronous driver interfaces. The library distinguishes itself through a decoupled protocol parser that converts raw byte streams into structured data objects independently of the network transport layer. It supports high-performance pipelining to batch multiple commands into a single network round-trip and provides a secure networking layer fo

Mosquitto is an MQTT message broker and IoT messaging server designed to route data between publishers and subscribers. It functions as a centralized network hub that enables lightweight communication between distributed sensors, controllers, and other internet-of-things devices. The project includes an MQTT bridging gateway used to link separate brokers, allowing traffic to be routed and synchronized across different network locations or security zones. It also provides a client implementation for connecting to and interacting with the broker. The system manages topic-based message routing

The php-standard-library is a comprehensive toolkit for functional programming and asynchronous networking in PHP, featuring typed data structures, structured concurrency, and composable validation mechanisms. It provides explicit result types and pure collection transformers that separate lists from dictionaries, eliminating traditional array key confusion and error-throwing patterns. The library supports concurrent execution through lightweight user-space fibers, message-passing channels, and non-blocking event loops, driving asynchronous TCP, TLS, UDP, and Unix socket servers without relyi

This is a Golang client library for interacting with a cloud native distributed messaging system. It provides the necessary tools for Go applications to exchange messages using publish-subscribe and request-reply patterns, as well as specialized clients for managing persistent streams and distributed storage. The library includes a JetStream client for durable message streaming and replay, a Key-Value store client for managing distributed state with versioning and watchers, and an Object Store client for the storage and retrieval of large binary files via chunked delivery. The implementation

Js-csp is a concurrency library that implements communicating sequential processes with channels and generator-based routines for asynchronous programming in JavaScript. It provides a framework for building data processing pipelines and managing concurrent workflows, bringing Go-style channels and process coordination primitives to applications. The library coordinates message passing through buffered channels, stream mixing, multi-channel selection, and pub-sub broadcasting. Communication pathways support unbuffered rendezvous, fixed buffers, sliding windows, and dropping overflow. Operation

Mongoose is an embedded networking library providing TCP/IP stacks, web server hosting, and IoT device connectivity. It enables microcontrollers and desktop systems to implement network protocols including HTTP, WebSocket, and MQTT. The project provides a bare-metal TCP/IP stack for environments without a native operating system and includes built-in TLS and ECC encryption to secure network traffic. It features a binary-embedded file system to serve web content directly from the executable and supports over-the-air firmware updates for managing device fleets. Additional capabilities cover as

Java-WebSocket is a collection of classes for implementing WebSocket clients and servers using pure Java. It provides a framework for hosting servers that manage connections via event-driven subclasses and tools for establishing client connections to remote servers. The library includes a secure communication tool for encrypting traffic using the WSS protocol and a compression library that uses per-message deflate extensions to reduce transmitted data size. It supports the configuration of cipher suites to limit encryption protocols and ensure compatible communication. The project enables bi

Gevent is a Python coroutine concurrency library and asynchronous task manager designed for high-concurrency I/O tasks. It provides a cooperative networking framework for building asynchronous TCP, UDP, and HTTP servers, as well as a WSGI web server implementation for hosting web applications. The project is distinguished by its standard library monkey-patching tool, which replaces blocking synchronous functions with cooperative versions to enable asynchronous behavior in third-party code. This allows for a cooperative multitasking workflow where the system yields execution during I/O waits t

Covenant is a .NET-based command and control framework designed for red team operations and adversary simulation. It serves as a collaborative platform for coordinating security assessments, managing remote implants, and executing tasks on compromised systems through a centralized server. The project is distinguished by its dynamic payload generator, which compiles and obfuscates executable binaries and scripts on the fly to bypass detection. It further separates itself through a collaborative environment that allows multiple authenticated operators to share a synchronized state, track operat

pyzmq provides Python language bindings for ZeroMQ, serving as an asynchronous messaging library for distributed data transport and inter-process communication. It enables the implementation of non-blocking communication patterns between distributed components and local processes. The toolkit focuses on high-performance data exchange through features such as zero-copy buffer access, which reads incoming messages directly into pre-allocated memory to avoid data duplication. It also supports the management of multipart messages and the use of state-shadowing object wrappers to track socket life