> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ninjachat.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# OpenAI Compatibility

> Use the official OpenAI SDKs with NinjaChat — just change the base URL and API key.

NinjaChat exposes an OpenAI-compatible `/chat/completions` endpoint. Point any
OpenAI SDK at NinjaChat by setting two things:

* **Base URL:** `https://www.ninjachat.ai/api/v1`
* **API key:** your `nj_sk_...` key

Everything else — request shape, streaming, tool calls, and error format — matches the OpenAI API.

<CodeGroup>
  ```python Python theme={null}
  from openai import OpenAI

  client = OpenAI(
      base_url="https://www.ninjachat.ai/api/v1",
      api_key="nj_sk_YOUR_API_KEY",
  )

  resp = client.chat.completions.create(
      model="gpt-5",
      messages=[{"role": "user", "content": "Hello!"}],
  )
  print(resp.choices[0].message.content)
  ```

  ```javascript Node.js theme={null}
  import OpenAI from "openai";

  const client = new OpenAI({
    baseURL: "https://www.ninjachat.ai/api/v1",
    apiKey: "nj_sk_YOUR_API_KEY",
  });

  const resp = await client.chat.completions.create({
    model: "gpt-5",
    messages: [{ role: "user", content: "Hello!" }],
  });
  console.log(resp.choices[0].message.content);
  ```
</CodeGroup>

## What works

* **Any model** — pass any [model ID](/models), or `auto` to let NinjaChat pick.
* **Streaming** — set `stream: true` for token-by-token server-sent events.
* **Tool calling** — standard `tools` / `tool_choice` with `function.parameters`.
* **Sampling** — `temperature`, `top_p`, `max_tokens` (or `max_completion_tokens`), `stop`, `seed`, `frequency_penalty`, `presence_penalty`.

```python theme={null}
# Streaming
for chunk in client.chat.completions.create(
    model="auto",
    messages=[{"role": "user", "content": "Write a haiku about the sea."}],
    stream=True,
):
    print(chunk.choices[0].delta.content or "", end="")
```

<Note>
  Both `/api/v1/chat/completions` (OpenAI-style) and `/api/v1/chat` (native)
  accept the same request and return the same response. Use whichever your tooling expects.
</Note>

## NinjaChat extras

The native [`/chat`](/chat) endpoint adds optional features OpenAI doesn't have —
[smart routing](/smart-routing), [fallback chains](/fallback-chains),
[budget routing](/budget-routing), [sessions](/sessions), and per-response `cost`
and `balance`. They're ignored by the OpenAI SDK, so you can adopt them gradually.