> ## Documentation Index
> Fetch the complete documentation index at: https://opentouter.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 — no boilerplate, no provider-specific quirks.

## Install instructions

| Language   | Package                                                            | Install                                   |
| ---------- | ------------------------------------------------------------------ | ----------------------------------------- |
| TypeScript | [`@openrouter/sdk`](https://www.npmjs.com/package/@openrouter/sdk) | `npm install @openrouter/sdk`             |
| Python     | [`openrouter`](https://pypi.org/project/openrouter/)               | `pip install openrouter`                  |
| Go         | [`go-sdk`](https://pkg.go.dev/github.com/OpenRouterTeam/go-sdk)    | `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](/agent-sdk/overview) instead.
</Tip>

## Quick example

<CodeGroup>
  ```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({
    model: 'openai/gpt-5.2',
    messages: [
      { role: 'user', content: 'Explain quantum computing in one sentence.' },
    ],
  });

  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)
  ```
</CodeGroup>

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