diff --git a/proxy/callback.functions.php b/proxy/callback.functions.php
index 47790b3..729880d 100644
--- a/proxy/callback.functions.php
+++ b/proxy/callback.functions.php
@@ -1,9 +1,13 @@
 <?php
 
 function civiproxy_callback_validate_request_method($expected, $actual){
-  if($expected != $actual){
-    civiproxy_http_error("Invalid request method.", 405);
+  if(is_array($expected) && in_array($actual, $expected)){
+    return;
   }
+  if(is_string($expected) && $expected == $actual){
+    return;
+  }
+  civiproxy_http_error("Invalid request method.", 405);
 }
 
 function civiproxy_callback_validate_content_type($expected, $actual){
diff --git a/proxy/config.php b/proxy/config.php
index 35413b0..cf6b84e 100644
--- a/proxy/config.php
+++ b/proxy/config.php
@@ -122,8 +122,8 @@ $callbacks_enabled = false;
 
 $callbacks = [
   'sparkpost' => [
-    // 'secret' => '',
-    'request_method' => 'POST',
+    'secret' => '85c573b980c3c248f083f9ca6a175659',
+    'request_method' => 'POST', // single value or array
     'content_type' => 'application/json',
     'target_path' => 'civicrm/sparkpost/callback'
   ]