diff --git a/lib/bugsnag.rb b/lib/bugsnag.rb
index 5d002a90..1b50ca85 100644
--- a/lib/bugsnag.rb
+++ b/lib/bugsnag.rb
@@ -535,6 +535,11 @@ def check_endpoint_setup
     # @return [String]
     def report_to_json(report)
       cleaned = cleaner.clean_object(report.as_json)
+
+      if Bugsnag::Helpers.payload_too_long?(cleaned)
+        configuration.warn("The notify payload is too large and will be truncated.")
+      end
+
       trimmed = Bugsnag::Helpers.trim_if_needed(cleaned)
 
       ::JSON.dump(trimmed)
diff --git a/lib/bugsnag/helpers.rb b/lib/bugsnag/helpers.rb
index 7a1c4178..cb43f5cf 100644
--- a/lib/bugsnag/helpers.rb
+++ b/lib/bugsnag/helpers.rb
@@ -71,6 +71,13 @@ def self.deep_merge!(l_hash, r_hash)
       end
     end
 
+    ##
+    # Validate that the serialized JSON string value is below maximum payload
+    # length
+    def self.payload_too_long?(value)
+      get_payload_length(value) >= MAX_PAYLOAD_LENGTH
+    end
+
     private
 
     TRUNCATION_INFO = '[TRUNCATED]'
@@ -156,13 +163,6 @@ def self.trim_strings_in_value(value)
       end
     end
 
-    ##
-    # Validate that the serialized JSON string value is below maximum payload
-    # length
-    def self.payload_too_long?(value)
-      get_payload_length(value) >= MAX_PAYLOAD_LENGTH
-    end
-
     def self.get_payload_length(value)
       if value.is_a?(String)
         value.length