&{...} 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: patterns navigate data, placeholders interpolate values into strings.
Syntax
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:
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.