diff --git a/back/config/util.ts b/back/config/util.ts
index 318aa041..77fef6bc 100644
--- a/back/config/util.ts
+++ b/back/config/util.ts
@@ -399,7 +399,7 @@ export function parseBody(
   valueFormatFn?: (v: string) => string,
 ) {
   if (contentType === 'text/plain' || !body) {
-    return body;
+    return valueFormatFn && body ? valueFormatFn(body) : body;
   }
 
   const parsed = parseString(body, valueFormatFn);
diff --git a/sample/notify.js b/sample/notify.js
index 9d17e16a..9351cefe 100644
--- a/sample/notify.js
+++ b/sample/notify.js
@@ -1379,7 +1379,7 @@ function parseHeaders(headers) {
 
 function parseBody(body, contentType, valueFormatFn) {
   if (contentType === 'text/plain' || !body) {
-    return body;
+    return valueFormatFn && body ? valueFormatFn(body) : body;
   }
 
   const parsed = parseString(body, valueFormatFn);
diff --git a/sample/notify.py b/sample/notify.py
index 2bd0f7ae..0e40fcbc 100644
--- a/sample/notify.py
+++ b/sample/notify.py
@@ -766,7 +766,7 @@ def parse_string(input_string, value_format_fn=None):
 
 def parse_body(body, content_type, value_format_fn=None):
     if not body or content_type == "text/plain":
-        return body
+        return value_format_fn(body) if value_format_fn and body else body
 
     parsed = parse_string(body, value_format_fn)