diff --git a/apps/explorer/mix.exs b/apps/explorer/mix.exs
index 417b978c70..366289e06d 100644
--- a/apps/explorer/mix.exs
+++ b/apps/explorer/mix.exs
@@ -97,7 +97,8 @@ defmodule Explorer.Mixfile do
       {:prometheus_ecto, "~> 1.3"},
       {:sobelow, ">= 0.7.0", only: [:dev, :test], runtime: false},
       {:timex, "~> 3.1.24"},
-      {:timex_ecto, "~> 3.2.1"}
+      {:timex_ecto, "~> 3.2.1"},
+      {:cowboy, "~> 1.0"}
     ]
   end