> ## Documentation Index
> Fetch the complete documentation index at: https://docs.alumio.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Placeholders

> Insert dynamic values from entity data into text fields using placeholder syntax.

Placeholders let you insert dynamic values from entity data into text fields at runtime. They use the `&{...}` syntax and work across most text fields in Alumio, such as values in the Value setter, templates in the Merger, and URL paths in HTTP transformers.

Placeholders are different from [patterns](/references/patterns) — patterns navigate data, placeholders interpolate values into strings.

## Syntax

| Syntax              | Description                                         |
| ------------------- | --------------------------------------------------- |
| `&{product.name}`   | The value at `product.name` in the entity           |
| `&{products.0.sku}` | The `sku` of the first product                      |
| `&{@}`              | The entire output of the current transformer        |
| `@{globals.<key>}`  | A global variable set by the Global variable setter |

## Examples

### Value setter

Set a field to a concatenated string:

**Key**: `full_name`
**Value**: `&{first_name} &{last_name}`

If the entity contains `first_name: "Jane"` and `last_name: "Doe"`, the result is:

```json theme={null}
{
    "full_name": "Jane Doe"
}
```

***

### Merger

Merge HTTP transformer output into the entity using a placeholder:

**Template**: `{ "response": "&{@}" }`

This captures the full output of the HTTP transformer and stores it under `response`.

***

### HTTP transformer URL

Use entity data in a request URL:

**URL**: `https://api.example.com/products/&{product.id}`

If `product.id` is `42`, the request goes to `https://api.example.com/products/42`.

## Notes

* Placeholders resolve at runtime — if the referenced path does not exist in the entity, the placeholder is replaced with an empty string.
* `&{@}` is only available in contexts that wrap a transformer output, such as the Merger.
* Global variables (`@{globals.<key>}`) must be set earlier in the route using the Global variable setter transformer.