WebSocket library in C++: complete guide to selection and usage

WebSocket library C++: modern tools for real-time applications

WebSocket is a protocol that provides a persistent bidirectional connection between a client and a server over TCP. Unlike HTTP, it allows data to be transmitted in real time without constant requests. For the C++ language, there are several powerful libraries implementing WebSocket. In this article, we will look at the three most popular ones: Boost.Beast, uWebSockets and websocketpp, and also provide practical examples of their use.

Why do you need a WebSocket library in C++?

Developing WebSocket from scratch is a complex task requiring a deep understanding of the protocol, connection management, and frame handling. Ready-made libraries offer:

• Full implementation of the RFC 6455 protocol
• Support for SSL/TLS encryption
• Management of multiple connections
• Handling of fragmented messages
• Ping/pong mechanisms for connection checking
• Asynchronous architecture for high performance

Boost.Beast — industry standard

Boost.Beast is a library based on Boost.Asio. It provides an implementation of HTTP and WebSocket protocols. It is considered the most reliable and performant solution for C++.

Installation:

# For Ubuntu/Debian:sudo apt install libboost-all-dev

# Or via vcpkg:vcpkg install boost-beast

Example of a simple WebSocket server:

#include <boost/beast/core.hpp>#include <boost/beast/websocket.hpp>#include <boost/asio.hpp>#include <iostream>#include <string>

namespace beast = boost::beast;namespace websocket = beast::websocket;namespace net = boost::asio;using tcp = net::ip::tcp;

int main() {    try {        net::io_context ioc;        tcp::acceptor acceptor(ioc, tcp::endpoint(tcp::v4(), 8080));

        while (true) {            tcp::socket socket(ioc);            acceptor.accept(socket);

            websocket::stream<tcp::socket> ws(std::move(socket));            ws.accept();

            for (int i = 0; i < 5; ++i) {                beast::flat_buffer buffer;                ws.read(buffer);                std::cout << "Received: " << beast::make_printable(buffer.data()) << std::endl;

                std::string response = "Server response: " + std::to_string(i);                ws.write(net::buffer(response));            }        }    } catch (std::exception const& e) {        std::cerr << "Error: " << e.what() << std::endl;    }    return 0;}

Features:

• Full integration with Boost.Asio (asynchronous operations)
• SSL support out of the box
• Minimal overhead on abstractions
• Extensive documentation and examples
• Used in production projects (e.g., in some game servers)

uWebSockets — lightweight and fast

uWebSockets is a library written in C++17 that focuses on maximum performance and minimal memory consumption. It supports both HTTP and WebSocket.

Installation:

git clone https://github.com/uNetworking/uWebSockets.gitcd uWebSocketsmakesudo make install

Example of a WebSocket server:

#include <uwebsockets/App.h>#include <iostream>

int main() {    uWS::App()        .ws("/*", {            .open = [](auto* ws) {                std::cout << "Client connected!" << std::endl;                ws->send("Welcome!", uWS::OpCode::TEXT);            },            .message = [