> ## 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.

# CreateOpenAICompatibleV4Middleware

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

***

[@ai-billing/openai-compatible](/docs/sdk/ai-billing/reference/openai-compatible/typedoc/index) / createOpenAICompatibleV4Middleware

# Function: createOpenAICompatibleV4Middleware()

> **createOpenAICompatibleV4Middleware**\<`TTags`>(`options`): `LanguageModelV4Middleware`

Defined in: [openai-compatible/src/ai-sdk/language-model-middleware/v4/language-model-v4-openai-compatible-billing-middleware.ts:87](https://github.com/narevai/ai-billing/blob/main/packages/openai-compatible/src/ai-sdk/language-model-middleware/v4/language-model-v4-openai-compatible-billing-middleware.ts#L87)

Creates a V4 billing middleware for OpenAI-compatible providers (for example `@ai-sdk/openai-compatible`).
Normalizes usage and resolves cost via your PriceResolver; billing events use `options.providerId`
as the provider.

## Type Parameters

### TTags

`TTags` *extends* `JSONObject`

The shape of the tags object, extending DefaultTags.

## Parameters

### options

[`OpenAICompatibleV4MiddlewareOptions`](/docs/sdk/ai-billing/reference/openai-compatible/typedoc/interfaces/OpenAICompatibleV4MiddlewareOptions)\<`TTags`>

Billing options; see [OpenAICompatibleV4MiddlewareOptions](/docs/sdk/ai-billing/reference/openai-compatible/typedoc/interfaces/OpenAICompatibleV4MiddlewareOptions).

## Returns

`LanguageModelV4Middleware`

A V4 billing middleware instance for the configured provider.

## Example

Targets AI SDK v7 (`LanguageModelV4Middleware`).

```ts theme={null}
import { createOpenAICompatible } from '@ai-sdk/openai-compatible';
import { wrapLanguageModel } from 'ai';
import { createOpenAICompatibleV4Middleware } from '@ai-billing/openai-compatible';
import {
  consoleDestination,
  createObjectPriceResolver,
  type ModelPricing,
} from '@ai-billing/core';
import type { LanguageModelV4 } from '@ai-sdk/provider';

const xai = createOpenAICompatible({
  name: 'xai', // must match `providerId` below
  baseURL: 'https://api.x.ai/v1',
  apiKey: process.env.XAI_API_KEY,
  includeUsage: true,
});

const customPricingMap: Record<string, ModelPricing> = {
  'grok-4-1-fast-reasoning': {
    promptTokens: 0.2 / 1_000_000,
    completionTokens: 0.5 / 1_000_000,
    internalReasoningTokens: 0,
    inputCacheReadTokens: 0.15 / 1_000_000,
  },
};

const priceResolver = createObjectPriceResolver(customPricingMap);

const billingMiddleware = createOpenAICompatibleV4Middleware({
  destinations: [consoleDestination()],
  priceResolver,
  providerId: 'xai',
});

const wrappedModel = wrapLanguageModel({
  model: xai('grok-4-1-fast-reasoning') as unknown as LanguageModelV4,
  middleware: billingMiddleware,
});
```