String transformation filters for Journey variables

Business problem

Different external systems often format the same data differently, such as Shopify including a # prefix in order numbers while shipping APIs require them without it. Currently, mapping a variable like {{ order_number }} directly into an HTTP Action URL fails because special characters (like the hash) break the query or are rejected by the target API. This forces users to build and maintain external middleware just to perform simple string manipulations.

Wished result

Integrated string transformation capabilities within Trengo Journeys to modify variable data before it is used in actions. This could be achieved through Liquid-style filters (e.g., {{ order_number | remove: '#' }}), a "Transform" option within the Set Variable step, or inline transformation mapping in HTTP Actions. Support for common operations like remove, replace, substring, regex, and case formatting would eliminate the need for external infrastructure for simple data cleaning.