diff --git a/packages/backend/src/helpers/compute-parameters.ts b/packages/backend/src/helpers/compute-parameters.ts
index c37328bd..62a9925d 100644
--- a/packages/backend/src/helpers/compute-parameters.ts
+++ b/packages/backend/src/helpers/compute-parameters.ts
@@ -2,7 +2,7 @@ import Step from '../models/step';
 import ExecutionStep from '../models/execution-step';
 import get from 'lodash.get';
 
-const variableRegExp = /({{step\.[\da-zA-Z-]+(?:\.[\da-zA-Z-]+)+}})/g;
+const variableRegExp = /({{step\.[\da-zA-Z-]+(?:\.[\da-zA-Z-_]+)+}})/g;
 
 export default function computeParameters(
   parameters: Step['parameters'],