HTTP Client for C++: Top Libraries for Networking

HTTP Client for C++: Overview of the Best Libraries

Developing network applications in C++ has traditionally been considered a complex task due to the lack of built-in HTTP support and the need to work with low-level sockets. However, modern libraries completely solve this problem by providing convenient, secure, and high-performance tools for sending HTTP requests, processing responses, and working with REST APIs. In this article, we will look at four of the most popular and mature solutions that will help you quickly integrate an HTTP client into your C++ project.

1. libcurl — The Universal Standard

libcurl is the most well-known and widely used library for data transfer over various protocols, including HTTP/HTTPS, FTP, SMTP, and many others. It is written in C but has an official wrapper for C++ (curl/curl.h). Key advantages: support for almost all HTTP versions (up to HTTP/3), working with proxies, authentication, SSL/TLS, multithreading, and a huge community.

Example of a simple GET request using libcurl:

#include <curl/curl.h>#include <string>

size_t WriteCallback(void* contents, size_t size, size_t nmemb, std::string* buffer) {    size_t totalSize = size * nmemb;    buffer->append(static_cast<char*>(contents), totalSize);    return totalSize;}

int main() {    CURL* curl = curl_easy_init();    if (curl) {        std::string response;        curl_easy_setopt(curl, CURLOPT_URL, "https://api.example.com/data");        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);

        CURLcode res = curl_easy_perform(curl);        if (res == CURLE_OK) {            // Work with response        }        curl_easy_cleanup(curl);    }    return 0;}

Disadvantages: C-style API (requires manual memory management), need to compile with linker flags (-lcurl).

2. cpp-httplib — Lightweight and Header-Only Library

cpp-httplib (by yhirose) is a modern, single-header (header-only) library for C++11 and above. It requires no external dependencies (except OpenSSL for HTTPS) and is ideal for small projects, microservices, and prototyping. Supports synchronous and asynchronous requests, cookies, timeouts, multipart/form-data.

Example of a POST request with JSON:

#include <httplib.h>

int main() {    httplib::Client cli("https://api.example.com");        httplib::Headers headers = {        {"Content-Type", "application/json"}    };        auto res = cli.Post("/submit", headers, R"({"key":"value"})", "application/json");        if (res && res->status == 200) {        std::cout << res->body << std::endl;    }    return 0;}

Pros: minimal entry barrier, no linking required, clean C++ code. Cons: limited support for advanced features (e.g., HTTP/2).

3. Boost.Beast — A Powerful Tool for Professionals

Boost.Beast is a library from the Boost team built on top of Boost.Asio. It provides low-level control over HTTP/1.x and WebSocket connections. Recommended for high-load systems where performance and asynchronous processing are important.

Example of an asynchronous HTTP client (fragment):

#include <boost/beast/core.hpp>#include <boost/beast/http.hpp>#include <boost/beast/version.hpp>#include <boost/asio/connect.hpp>#include <boost/asio/ip/tcp.hpp>

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

int main() {    net::io_context ioc;    tcp::resolver resolver(ioc);    beast::tcp_stream stream(ioc);

    auto const results = resolver.resolv