Modern C++ LLM API client with openai-compatible support

Clean, type-safe LLM API client using C++23 modules. Fluent interface with zero-cost abstractions. Works with OpenAI, Poe, DeepSeek and compatible endpoints.

• C++23 Modules - import mcpplibs.llmapi
• Auto-Save History - Conversation history managed automatically
• Type-Safe Streaming - Concept-constrained callbacks
• Fluent Interface - Chainable methods
• C API - Full C language support with OOP style
• Provider Agnostic - OpenAI, Poe, and compatible endpoints

import std;
import mcpplibs.llmapi;

int main() {
    using namespace mcpplibs;
    
    llmapi::Client client(std::getenv("OPENAI_API_KEY"), llmapi::URL::Poe);

    client.model("gpt-5")
          .system("You are a helpful assistant.")
          .user("In one sentence, introduce modern C++. 并给出中文翻译")
          .request([](std::string_view chunk) {
                std::print("{}", chunk);
                std::cout.flush();
          });

    return 0;
}

#include <stdio.h>

#include "llmapi.h"

void stream_print(const char* s, size_t len, void* data) {
    printf("%.*s", (int)len, s);
    fflush(stdout);
}

int main(void) {
    llmapi_client_t* c = llmapi_client_create(getenv("OPENAI_API_KEY"), LLMAPI_URL_POE);

    c->set_model(c, "gpt-5");
    c->add_system_message(c, "You are a helpful assistant.");
    c->add_user_message(c, "In one sentence, introduce modern C++. 并给出中文翻译");
    c->request_stream(c, stream_print, NULL);
    
    c->destroy(c);
    return 0;
}

llmapi::Client client(apiKey, llmapi::URL::OpenAI);    // OpenAI
llmapi::Client client(apiKey, llmapi::URL::Poe);       // Poe
llmapi::Client client(apiKey, llmapi::URL::DeepSeek);  // Deepseek
llmapi::Client client(apiKey, "https://custom.com");   // Custom

xmake              # Build
xmake run basic    # Run example(after cofig OPENAI_API_KEY)

-- 0 - Add mcpplibs's index repos
add_repositories("mcpplibs-index git@github.com:mcpplibs/mcpplibs-index.git")

-- 1 - Add the libraries and versions you need
add_requires("llmapi 0.0.1")
-- add_requires("llmapi 0.0.1", configs = { capi = true }) -- if use c api

More: mcpplibs-index

todo...

C++ Core Methods:

• model(name) - Set model
• user/system/assistant(content) - Add messages
• request() - Non-streaming (returns JSON)
• request(callback) - Streaming
• getAnswer() - Get last assistant reply
• getMessages() - Get conversation history
• clear() - Clear history

C API: All methods available via function pointers (client->method(client, ...))

Apache-2.0 - see LICENSE