cozyweb

Single file C99 header cross-platform networking libraries.

Library	Purpose	Description	LOC	Version
udp.h	Real-time communication	Non-blocking UDP client/server for games, VOIP, and other low-latency applications	573	1.0.0
https.h	Web resources	Simple HTTP/HTTPS client with one-function GET requests and asynchronous processing	438	1.0.0

Why cozyweb?

• Minimal API surface - Simple functions that do exactly what you need.
• Zero dependencies - No external libraries required.
• Non-blocking by default - Perfect for game loops and UI applications.
• Single-file implementation - Just include and go.
• Battle-tested - Powers my games and put under real world stress with a VOIP App usable across countries.

Getting Started

Include a library in your project with just two lines:

#define UDP_IMPLEMENTATION  // or HTTPS_IMPLEMENTATION
#include "udp.h"            // or "https.h"

Or include it in a separate source file if you prefer to build it separately.

Libraries

📡 udp.h

A lightweight UDP library for building real-time networked applications:

• Asynchronous, non-blocking I/O
• Simple client and server implementations
• Designed for game networking and voice applications
• Cross-platform with minimal OS-specific code

// UDP client example
udp_conn* client = udp_connect(udp_resolve_host("localhost", "30000", true, &(udp_addr){}), false);
udp_send(client, "Hello!", 7);
    
// Non-blocking poll based receive - perfect for game loops
while(!udp_recv(client));

printf("Got: %.*s\n", (int)client->data_len, (char*)client->data);

🌐 https.h

A straightforward HTTP/HTTPS client that makes web requests painless:

• One function call for GET requests
• Asynchronous by default
• Minimal memory footprint
• Clean API for handling responses

// Simple HTTP/HTTPS GET request
https_req* req = https_get("https://api.example.com/data");
while(req->state == HTTPS_PENDING); // Busy sleep while request resolves in another thread

// Check if complete (non-blocking)
if(req->state == HTTPS_COMPLETE) {
  printf("Response (Status: %d): %.*s\n", req->status_code, (int)req->data_len, (char*)req->data);
  https_free(req);
}

Real-World Examples

• VOIP Application: A complete cross-platform voice chat system in just 200 lines of code in voip.c.
• Examples Directory: Sample code for UDP servers and HTTP clients

Performance

These libraries prioritize efficiency alongside ease of use:

• udp.h: Direct wrapper around native socket APIs for minimal overhead
• https.h: Performance comparable to cURL with support for concurrent requests

Platform Support

• udp.h: Any system with BSD sockets (Windows, macOS, Linux, etc.)
• https.h: Currently Windows-only (WinHTTP), with cURL support coming soon

License

Dual-licensed under MIT and Public Domain. Choose the license that best suits your project:

• MIT: Simple permissive license
• Public Domain: No copyright, completely free for any use

FAQ

How does cozyweb compare to alternatives?

My aim was to remove all of the boilerplate and complexity that comes with interfacing with the web in C. I hated dealing with threads, learning about edge cases and library internals and having to know the HTTP/s protocol to even make a basic FETCH request. This is easy in languages like Javascript, so why not C? I couldn't find the answer to that, so I engineered a solution myself.

In short, cozyweb is the simplest set of web libraries you will ever come across for C. While I may not offer every possible feature, I guarantee an exceptional developer experience and top-tier performance.

Are there alternatives?

If cozyweb doesn't meet your needs, consider:

• cute_headers
• http.h
• enet
• SDL_net

Sample Programs

Complete sample programs to show how they work and common practices:

udp.h

#include <stdio.h>

#define UDP_IMPLEMENTATION
#include "udp.h"

int main() {
    udp_conn* client = udp_connect(udp_resolve_host("localhost", "30000", true, &(udp_addr){}), false);
    if(client->error) {
      printf("Error %d: %s\n", client->error, udp_error_str(client->error));
      return 1;
    }

    udp_send(client, "Hello from client!", sizeof("Hello from client!"));
    
    while(!udp_recv(client)); // Wait for a response from the server.
    printf("Received \"%.*s\"\n", (int) client->data_len, (char*) client->data);

    udp_close_n_free(client);
}

https.h

#include <stdio.h>

#define HTTPS_IMPLEMENTATION
#include "https.h"

int main(int argc, char** argv) {
    https_req* req = https_get(argc == 1 ? argv[0] : "https://www.google.com/"); // http works too!
    while(req->state == HTTPS_PENDING);// Sleep(20); // Wait for the request to complete.

    if(req->state != HTTPS_COMPLETE) {
        printf("Failed to get response\nStatus Code: %d\nReason: %s", req->status_code,
               req->req_failed_reason);
        https_free(req);
        return 1;
    }

    printf("Response (Status: %d): %.*s\n", req->status_code, (int)req->data_len, (char*)req->data);
    https_free(req);
}