# SchemaWithFallbackAsync

> This document is the Markdown version of [valibot.dev/api/SchemaWithFallbackAsync/](https://valibot.dev/api/SchemaWithFallbackAsync/). For the complete documentation index, see [llms.txt](https://valibot.dev/llms.txt).

Schema with fallback async type.

## Generics

- `TSchema` `extends BaseSchema<unknown, unknown, BaseIssue<unknown>> | BaseSchemaAsync<unknown, unknown, BaseIssue<unknown>>`
- `TFallback` `extends FallbackAsync<TSchema>`

## Definition

- `SchemaWithFallbackAsync` `extends Omit<TSchema, 'async' | '~run'>`
  - `fallback` `TFallback`
  - `async` `true`
  - `~run` `(dataset: UnknownDataset, config: Config<BaseIssue<unknown>>) => Promise<OutputDataset<InferOutput<TSchema>, InferIssue<TSchema>>>`