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

# CreateOpenRouterV4Middleware

[**@ai-billing/openrouter**](../index)

***

[@ai-billing/openrouter](/docs/sdk/ai-billing/reference/openrouter/typedoc/index) / createOpenRouterV4Middleware

# Function: createOpenRouterV4Middleware()

> **createOpenRouterV4Middleware**\<`TTags`>(`options`): `LanguageModelV4Middleware`

Defined in: [language-model-middleware/v4/language-model-v4-openrouter-billing-middleware.ts:70](https://github.com/narevai/ai-billing/blob/main/packages/openrouter/src/ai-sdk/language-model-middleware/v4/language-model-v4-openrouter-billing-middleware.ts#L70)

Creates a V4 billing middleware for OpenRouter (`@openrouter/ai-sdk-provider`).
Extracts cost and usage from `openrouter` provider metadata; requires numeric `usage.cost`.

## Type Parameters

### TTags

`TTags` *extends* `JSONObject`

The shape of the tags object, extending DefaultTags.

## Parameters

### options

[`OpenRouterV4MiddlewareOptions`](/docs/sdk/ai-billing/reference/openrouter/typedoc/type-aliases/OpenRouterV4MiddlewareOptions)\<`TTags`>

Shared billing options; see BaseBillingMiddlewareOptions.

## Returns

`LanguageModelV4Middleware`

A V4 billing middleware instance for OpenRouter.

## Example

Targets AI SDK v7 (`LanguageModelV4Middleware`).

```ts theme={null}
import { createOpenRouter } from '@openrouter/ai-sdk-provider';
import { wrapLanguageModel } from 'ai';
import { createOpenRouterV4Middleware } from '@ai-billing/openrouter';
import { consoleDestination } from '@ai-billing/core';

const openrouter = createOpenRouter({
  apiKey: process.env.OPENROUTER_API_KEY,
});

const billingMiddleware = createOpenRouterV4Middleware({
  destinations: [consoleDestination()],
});

const wrappedModel = wrapLanguageModel({
  model: openrouter('google/gemini-2.0-flash-001'),
  middleware: billingMiddleware,
});
```