> ## Documentation Index > Fetch the complete documentation index at: https://openrouter.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # BatchProviderPreferences Batch provider routing preferences. Only `provider.only` and `provider.allow_fallbacks` are supported. ## Fields | Field | Type | Required | Description | Example | | - | - | - | - | - | | `AllowFallbacks` | optionalnullable.OptionalNullable\[`bool`] | ➖ | Whether to allow backup providers to serve requests - true: (default) when the primary provider (or your custom providers in "order") is unavailable, use the next best provider. - false: use only the primary/custom provider, and return the upstream error if it's unavailable. | | | `Only` | optionalnullable.OptionalNullable\[\[][components.BatchProviderPreferencesOnly](../../models/components/batchproviderpreferencesonly.mdx)] | ➖ | List of provider slugs to allow. If provided, this list is merged with your account-wide allowed provider settings for this request. | \[ "openai", "anthropic" ] |