# `customProvider()`

With a custom provider, you can map ids to any model.
This allows you to set up custom model configurations, alias names, and more.
The custom provider also supports a fallback provider, which is useful for
wrapping existing providers and adding additional functionality.

### Example: custom model settings

You can create a custom provider using `customProvider`.

```ts
import { openai } from '@ai-sdk/openai';
import { customProvider } from 'ai';

// custom provider with different model settings:
export const myOpenAI = customProvider({
  languageModels: {
    // replacement model with custom settings:
    'gpt-4': wrapLanguageModel({
      model: openai('gpt-4'),
      middleware: defaultSettingsMiddleware({
        settings: {
          providerOptions: {
            openai: {
              reasoningEffort: 'high',
            },
          },
        },
      }),
    }),
    // alias model with custom settings:
    'gpt-4o-reasoning-high': wrapLanguageModel({
      model: openai('gpt-4o'),
      middleware: defaultSettingsMiddleware({
        settings: {
          providerOptions: {
            openai: {
              reasoningEffort: 'high',
            },
          },
        },
      }),
    }),
  },
  fallbackProvider: openai,
});
```

## Import

<Snippet text={`import {  customProvider } from "ai"`} prompt={false} />

## API Signature

### Parameters

<PropertiesTable
  content={[
    {
      name: 'languageModels',
      type: 'Record<string, LanguageModel>',
      isOptional: true,
      description:
        'A record of language models, where keys are model IDs and values are LanguageModel instances.',
    },
    {
      name: 'textEmbeddingModels',
      type: 'Record<string, EmbeddingModel<string>>',
      isOptional: true,
      description:
        'A record of text embedding models, where keys are model IDs and values are EmbeddingModel<string> instances.',
    },
    {
      name: 'imageModels',
      type: 'Record<string, ImageModel>',
      isOptional: true,
      description:
        'A record of image models, where keys are model IDs and values are ImageModelV2 instances.',
    },
    {
      name: 'fallbackProvider',
      type: 'Provider',
      isOptional: true,
      description:
        'An optional fallback provider to use when a requested model is not found in the custom provider.',
    },
  ]}
/>

### Returns

The `customProvider` function returns a `Provider` instance. It has the following methods:

<PropertiesTable
  content={[
    {
      name: 'languageModel',
      type: '(id: string) => LanguageModel',
      description:
        'A function that returns a language model by its id (format: providerId:modelId)',
    },
    {
      name: 'textEmbeddingModel',
      type: '(id: string) => EmbeddingModel<string>',
      description:
        'A function that returns a text embedding model by its id (format: providerId:modelId)',
    },
    {
      name: 'imageModel',
      type: '(id: string) => ImageModel',
      description:
        'A function that returns an image model by its id (format: providerId:modelId)',
    },
  ]}
/>


## Navigation

- [generateText](/v5/docs/reference/ai-sdk-core/generate-text)
- [streamText](/v5/docs/reference/ai-sdk-core/stream-text)
- [generateObject](/v5/docs/reference/ai-sdk-core/generate-object)
- [streamObject](/v5/docs/reference/ai-sdk-core/stream-object)
- [embed](/v5/docs/reference/ai-sdk-core/embed)
- [embedMany](/v5/docs/reference/ai-sdk-core/embed-many)
- [generateImage](/v5/docs/reference/ai-sdk-core/generate-image)
- [transcribe](/v5/docs/reference/ai-sdk-core/transcribe)
- [generateSpeech](/v5/docs/reference/ai-sdk-core/generate-speech)
- [tool](/v5/docs/reference/ai-sdk-core/tool)
- [dynamicTool](/v5/docs/reference/ai-sdk-core/dynamic-tool)
- [experimental_createMCPClient](/v5/docs/reference/ai-sdk-core/create-mcp-client)
- [Experimental_StdioMCPTransport](/v5/docs/reference/ai-sdk-core/mcp-stdio-transport)
- [jsonSchema](/v5/docs/reference/ai-sdk-core/json-schema)
- [zodSchema](/v5/docs/reference/ai-sdk-core/zod-schema)
- [valibotSchema](/v5/docs/reference/ai-sdk-core/valibot-schema)
- [ModelMessage](/v5/docs/reference/ai-sdk-core/model-message)
- [UIMessage](/v5/docs/reference/ai-sdk-core/ui-message)
- [validateUIMessages](/v5/docs/reference/ai-sdk-core/validate-ui-messages)
- [safeValidateUIMessages](/v5/docs/reference/ai-sdk-core/safe-validate-ui-messages)
- [createProviderRegistry](/v5/docs/reference/ai-sdk-core/provider-registry)
- [customProvider](/v5/docs/reference/ai-sdk-core/custom-provider)
- [cosineSimilarity](/v5/docs/reference/ai-sdk-core/cosine-similarity)
- [wrapLanguageModel](/v5/docs/reference/ai-sdk-core/wrap-language-model)
- [LanguageModelV2Middleware](/v5/docs/reference/ai-sdk-core/language-model-v2-middleware)
- [extractReasoningMiddleware](/v5/docs/reference/ai-sdk-core/extract-reasoning-middleware)
- [simulateStreamingMiddleware](/v5/docs/reference/ai-sdk-core/simulate-streaming-middleware)
- [defaultSettingsMiddleware](/v5/docs/reference/ai-sdk-core/default-settings-middleware)
- [stepCountIs](/v5/docs/reference/ai-sdk-core/step-count-is)
- [hasToolCall](/v5/docs/reference/ai-sdk-core/has-tool-call)
- [simulateReadableStream](/v5/docs/reference/ai-sdk-core/simulate-readable-stream)
- [smoothStream](/v5/docs/reference/ai-sdk-core/smooth-stream)
- [generateId](/v5/docs/reference/ai-sdk-core/generate-id)
- [createIdGenerator](/v5/docs/reference/ai-sdk-core/create-id-generator)


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