diff --git a/lib/api_taster/route.rb b/lib/api_taster/route.rb
index 06fd747..f0e05d5 100644
--- a/lib/api_taster/route.rb
+++ b/lib/api_taster/route.rb
@@ -31,6 +31,7 @@ def normalise_routes!
         end
 
         route_set.routes.each do |route|
+          next if route.app.is_a?(ActionDispatch::Routing::Mapper::Constraints)
           next if route.app.is_a?(Sprockets::Environment)
           next if route.app == ApiTaster::Engine