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

# Client SDKs

> Lightweight, type-safe clients for the OpenRouter API

The Client SDKs give you a thin, type-safe layer over the OpenRouter REST API. It handles authentication, request validation, and response typing so you can call any of 400+ models with a single function call, with no boilerplate and no provider-specific quirks.

## Installation

| Language | Package |
| - | - |
| TypeScript | [`@openrouter/sdk`](https://www.npmjs.com/package/@openrouter/sdk) |
| Python | [`openrouter`](https://pypi.org/project/openrouter/) |
| Go | [`go-sdk`](https://pkg.go.dev/github.com/OpenRouterTeam/go-sdk) |

```bash title="npm" lines theme={null}
npm install @openrouter/sdk
```

```bash title="pnpm" lines theme={null}
pnpm add @openrouter/sdk
```

```bash title="yarn" lines theme={null}
yarn add @openrouter/sdk
```

```bash title="bun" lines theme={null}
bun add @openrouter/sdk
```

```bash title="deno" lines theme={null}
deno add npm:@openrouter/sdk
```

```bash title="pip" lines theme={null}
pip install openrouter
```

```bash title="go" lines theme={null}
go get github.com/OpenRouterTeam/go-sdk
```

All three SDKs are auto-generated from the OpenRouter OpenAPI spec, so new models, parameters, and endpoints appear immediately after each API release.

## When to use the Client SDKs

Choose the Client SDKs when you need **direct, efficient access to model inference** and want to manage your own application logic:

* **Single-turn completions**, send a prompt, get a response
* **Streaming responses**, real-time token-by-token output
* **Embeddings, video, and rerank**, generate vector representations, create videos, and rerank results
* **API key and credit management**, programmatic control over your account
* **Custom orchestration**, you handle conversation loops, tool dispatch, and state yourself

The Client SDKs are intentionally lean. It mirrors the OpenRouter API surface 1:1 with full type safety, so there is no abstraction to fight when you need fine-grained control.

> [!TIP]
>
> If you want higher-level primitives for building agents (multi-turn loops, tool definitions, stop conditions, and conversation state management), see the [Agent SDK](/docs/agent-sdk/overview) instead.

## Quick example

```typescript title="TypeScript" lines theme={null}
import { OpenRouter } from '@openrouter/sdk';

const client = new OpenRouter({
  apiKey: process.env.OPENROUTER_API_KEY,
});

const response = await client.chat.send({
  chatRequest: {
    model: 'openai/gpt-5.2',
    messages: [
      { role: 'user', content: 'Explain quantum computing in one sentence.' },
    ],
  },
});

if (response instanceof ReadableStream) {
  throw new Error('Expected a non-streaming response');
}

console.log(response.choices[0].message.content);
```

```python title="Python" lines theme={null}
from openrouter import OpenRouter
import os

with OpenRouter(api_key=os.getenv("OPENROUTER_API_KEY")) as client:
    response = client.chat.send(
        model="openai/gpt-5.2",
        messages=[
            {"role": "user", "content": "Explain quantum computing in one sentence."}
        ],
    )

    print(response.choices[0].message.content)
```

## Client SDKs vs Agent SDK

| | Client SDKs | Agent SDK |
| - | - | - |
| **Focus** | Lean API client, mirrors the REST API with full type safety | Agentic primitives, multi-turn loops, tools, stop conditions |
| **Use when** | You want direct model calls and manage orchestration yourself | You want built-in agent loops, tool execution, and state management |
| **Conversation state** | You manage it | Managed for you via `callModel` |
| **Tool execution** | You dispatch tool calls | Automatic with the `tool()` helper |
| **Languages** | TypeScript, Python, Go | TypeScript |

## Next steps

* [TypeScript SDK reference](/docs/client-sdks/typescript)
* [Python SDK reference](/docs/client-sdks/python)
* [Go SDK reference](/docs/client-sdks/go)
* [Agent SDK overview](/docs/agent-sdk/overview), for building agents with multi-turn loops and tools