# Any

The **`any`** type accepts a value of **any** type. It is the default when a field is declared without a type (`name` is the same as `name: any`). You can still narrow it with `choices` or, for a union of types, `anyOf`.

```ruby
a, b: any, c: { type: any }
---
~ hello, 42, T        # ✓ — anything goes
```

## Declaring alternatives (anyOf)

`anyOf` lets a field accept any one of several types or MemberDefs — Internet Object's union type.

```ruby
id: { any, anyOf: [string, int] }
---
~ 42        # ✓ matches int
~ abc       # ✓ matches string
```

```ruby
flag: { any, anyOf: [bool, int] }
---
~ hello     # ✗ matches neither
```

Each alternative may be a full MemberDef or a SchemaDef:

```ruby
value: { any, anyOf: [{ int, multipleOf: 5 }, { int, multipleOf: 3 }] }
---
~ 10        # ✓ multiple of 5
~ 9         # ✓ multiple of 3
```

## TypeDef

An `any` MemberDef accepts only the options below.

| Option     | Type                    | Description                                                  |
| ---------- | ----------------------- | ------------------------------------------------------------ |
| `type`     | string                  | The type name `any`.                                         |
| `default`  | any                     | Value used when the member is omitted.                       |
| `choices`  | array                   | Restricts the value to a fixed set (of any type).            |
| `anyOf`    | array of MemberDef/type | The value must match one of these.                           |
| `optional` | bool                    | If `true`, the member may be omitted. Shorthand: `?` suffix. |
| `null`     | bool                    | If `true`, the member may be `null`. Shorthand: `*` suffix.  |

## choices

```ruby
pick: { any, choices: [1, One, T] }
---
~ One       # ✓
~ Two       # ✗ invalid-choice
```

## Optional, nullable & defaults

```ruby
note?*: any
---
~ {}        # ✓ omitted → absent
~ N         # ✓ null
```

## Implementation status (beta)

* Keyed `null:` is not yet honored — use the `*` suffix.

## See Also

* [Union Types (anyOf)](/schema-definition-language/advanced-schema-concepts/union-types.md)
* [TypeDef](/schema-definition-language/advanced-schema-concepts/typedef.md) · [MemberDef](/schema-definition-language/advanced-schema-concepts/memberdef.md)


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