Introduction

This crate exposes an async stream API for the widely-used OpenAI chat completion API.

Supported features:

• Stream generation
• Tool calls
• Reasoning content (Qwen3, Deepseek R1, etc) This crate is built on top of reqwest and serde_json.

use nah_chat::{ChatClient, ChatMessage};
use futures_util::{pin_mut, StreamExt};

let chat_client = ChatClient::init(base_url, auth_token);

// create and pin the stream
let stream = chat_client
       .chat_completion_stream(model_name, &messages, &params)
       .await
       .unwrap();
pin_mut!(stream);

// buffer for the new message
let mut message = ChatMessage::new();

// consume the stream
while let Some(delta_result) = stream.next().await {
  match delta_result {
    Ok(delta) => {
      message.apply_model_response_chunk(delta);
    }
    Err(e) => {
      eprintln!("Error occurred while processing the chat completion: {}", e);
    }
  }
}

Notice

Copyright 2025, Mengxiao Lin. This is a part of nah project. nah means "Not A Human". Source code is available under MPL-2.0.