> ## Documentation Index
> Fetch the complete documentation index at: https://docs.awaitio.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Input Boolean
> Asks a yes or no question with a checkbox.
`io.input.boolean()` asks a yes or no question and returns `true` or `false`. Provided by the `@awaitio/input-boolean` package.
## Install
```bash theme={null}
npm install @awaitio/input-boolean
```
## Setup
Register it under the key you want in `io`, see [Input components](/core/components):
```ts app.ts {5} theme={null}
import { inputBoolean } from '@awaitio/input-boolean';
export const app = new AwaitIO({
// name, actionsDirectory, theme, secret, users…
components: { input: { boolean: inputBoolean } },
});
```
## Usage
```ts theme={null}
const sendEmail = await io.input.boolean('Send a confirmation email', {
defaultValue: true,
helpText: 'The customer gets a copy of the change',
});
```
## Props
| Prop | Type | Required | Description |
| - | - | - | - |
| `helpText` | `string` | Required | Shown to the right of the checkbox: what checking it means. |
| `defaultValue` | `boolean` | Optional | Whether the box starts checked. Defaults to `false`. |
| `disabled` | `boolean` | Optional | Shows the starting value without letting it change; the handler gets that value whatever the browser sends. |
## Returns
`boolean`: `true` when the box is checked, `false` when it is not.
## Built-in validation
Nothing is checked: an unchecked box gives `false`.
## Custom validation
Chain `.validate()` for a check of your own. It runs on the server after the checks above, gets the value the handler would get and returns a message to show under the field, or nothing when the value is fine; see [Custom validation](/core/components#custom-validation).
```ts theme={null}
await io.input.boolean('I have read the refund policy').validate((isChecked) => {
return isChecked ? undefined : 'Read the refund policy first.';
});
```
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