HTTP Client for C++: Top Libraries for Network Programming

HTTP client for C++: overview of the best libraries

When developing modern applications in C++, it is rarely possible to avoid interacting with remote servers. Whether it's downloading data, sending forms, working with REST API, or simply parsing web pages, a reliable HTTP client for C++ is necessary. In this article, we will review four best libraries that will help you work with the HTTP protocol easily and efficiently.

1. cpp-httplib — simplicity and lightness

cpp-httplib (or simply httplib) is a header-only library that requires no installation. It is ideal for small projects where you don't want to deal with dependencies.

• Pros: minimalist API, works out of the box, supports HTTPS (via OpenSSL).
• Cons: limited functionality (no multithreaded requests, no WebSocket).

#include <httplib.h>#include <iostream>

int main() {    httplib::Client cli("http://jsonplaceholder.typicode.com");        auto res = cli.Get("/posts/1");    if (res && res->status == 200) {        std::cout << "Response: " << res->body << std::endl;    }    return 0;}

2. libcurl — the proven veteran

libcurl is the de facto standard for working with HTTP in C/C++. It is used in thousands of projects, including web servers and command-line utilities. Requires library installation and linking.

• Pros: huge number of protocols (HTTP/2, FTP, SMTP, WebSocket), cross-platform, high performance.
• Cons: C-style API (inconvenient for C++), complex multithreading setup.

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

size_t WriteCallback(void* contents, size_t size, size_t nmemb, std::string* output) {    size_t total = size * nmemb;    output->append((char*)contents, total);    return total;}

int main() {    CURL* curl = curl_easy_init();    if (curl) {        std::string response;        curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);        curl_easy_perform(curl);        curl_easy_cleanup(curl);    }    return 0;}

3. Boost.Beast — the power of Boost and asynchrony

Boost.Beast is part of the Boost ecosystem, providing low-level HTTP and WebSocket capabilities. The library is built on Boost.Asio, giving full control over asynchronous operations.

• Pros: full asynchrony, support for HTTP/1.1, WebSocket, compatibility with C++17/20.
• Cons: requires deep understanding of Asio, large amount of code for simple requests.

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

namespace beast = boost::beast;namespace http = beast::http;namespace net = boost::asio;

int main() {    net::io_context ioc;    beast::tcp_stream stream(ioc);    stream.connect("httpbin.org", 80);

    http::request<http::string_body> req{http::verb::get, "/get", 11};    req.set(http::field::host, "httpbin.org");    http::write(stream, req);

    beast::flat_buffer buffer;    http::response<http::dynamic_body> res;    http::read(stream, buffer, res);    std::cout << beast::buffers_to_string(res.body().data()) << std::endl;    return 0;}

4. Poco — the corporate standard

Poco (POrtable COmponents) is a full-fledged framework for C++, including HTTP client, server, network sockets, working with XML/JSON