chat-openai

OpenAI provider for chat-rs. Thin wrapper over chat-responses — presets https://api.openai.com/v1 and OPENAI_API_KEY, adds the OpenAI-specific native tools (web_search, image_generation) and the /embeddings endpoint (which is not part of the Responses API).

Install

[dependencies]
chat-core = "0.4.0"
chat-openai = "0.3.3"
tokio = { version = "1", features = ["macros", "rt-multi-thread"] }

Or via the umbrella crate: chat-rs = { version = "0.5.0", features = ["openai"] }.

Usage

use chat_openai::OpenAIBuilder;
use chat_core::{builder::ChatBuilder, types::messages};

let client = OpenAIBuilder::new()
    .with_model("gpt-4o")
    .build();

let mut chat = ChatBuilder::new().with_model(client).build();

let mut msgs = messages::from_user(vec!["Hello!"]);
let response = chat.complete(&mut msgs).await?;

Set OPENAI_API_KEY in your environment or call .with_api_key() on the builder.

Capabilities

• Completions — text generation with tool calling and structured output, via the Responses API
• Streaming — SSE token streaming (requires stream feature)
• Embeddings — vector embeddings via .with_embeddings() (uses OpenAI's /embeddings, not Responses)
• Reasoning effort — .with_reasoning_effort(effort) for o1/o3/GPT-5 reasoning models
• Previous-response-id round-tripping — server-side context resume (default on; disable with .without_previous_response_id())

Native Tools

• Web Search — .with_web_search(context_size, user_location)
• Image Generation — .with_image_generation(tool)

Transport

The default transport is HTTP/SSE via reqwest. To use WebSocket streaming:

use chat_openai::OpenAIBuilder;
use chat_core::transport::AsyncWsTransport;

let ws = AsyncWsTransport::new()
    .with_message_type("response.create");

let client = OpenAIBuilder::new()
    .with_model("gpt-4o")
    .with_transport(ws)
    .build();

Requires the tokio-tungstenite feature. A sync variant (WsTransport) is available via the tungstenite feature.

You can also supply any custom Transport implementation via .with_transport().

Custom Endpoints

Point at local or proxy servers implementing the Responses API:

let client = OpenAIBuilder::new()
    .with_model("custom-model")
    .with_custom_url("https://my-gateway/v1".to_string())
    .with_api_key("...".to_string())
    .build();

For full direct control of the Responses wire (no OpenAI defaults), use chat-responses directly.

Feature Flags

# Streaming
chat-openai = { version = "0.3.2", features = ["stream"] }

# WebSocket transport (requires the chat-core feature)
chat-openai = { version = "0.3.2", features = ["stream"] }
chat-core   = { version = "0.3.0", features = ["tokio-tungstenite"] }