diff --git a/public/index.php b/public/index.php
index 8fae0d4..5920c75 100644
--- a/public/index.php
+++ b/public/index.php
@@ -23,9 +23,10 @@ function config(string $key): bool|string|int|float {
     }
     foreach (require $config_override_path as $override_key => $override_value) {
         if (!array_key_exists($override_key, $config)) {
-            throw new Exception('Undefined key in config override file');
+            trigger_error('Undefined key in config file', E_USER_ERROR);
         }
         if (gettype($override_value) !== gettype($config[$override_key])) {
+            trigger_error('Type mismatch in config file', E_USER_ERROR);
             throw new Exception('Type mismatch in config override file');
         }
         $config[$override_key] = $override_value;
@@ -56,7 +57,7 @@ function json_response(mixed $data, int $status_code = 200)
 /**
  * Helper for reading and decoding JSON from request body
  */
-function json_decode_input(): array
+function json_decode_input(): array|bool|null
 {
     return json_decode(file_get_contents('php://input'), true);
 }