diff --git a/test/json_differ_test.exs b/test/json_differ_test.exs
new file mode 100644
index 0000000..458adf0
--- /dev/null
+++ b/test/json_differ_test.exs
@@ -0,0 +1,19 @@
+defmodule LiveState.Test.JsonDifferTest do
+  use ExUnit.Case
+
+  test "performance" do
+    map = Enum.reduce(1..1_00000, %{}, fn i, map ->
+      Map.put(map, "foo_#{i}", "bar")
+    end)
+    map2 = map |> Map.put("foo_997", "bing")
+    {usec, _} = :timer.tc(fn ->
+      json1 = Jason.encode!(map)
+      json2 = Jason.encode!(map2)
+
+      LiveState.JSONDiffer.build_patch_message(json1, json2, 2)
+    end)
+    IO.inspect(usec / 1_000, label: "rust json diffing")
+    {elixir_usec, _} = :timer.tc(&JSONDiff.diff/2, [map, map2])
+    IO.inspect(elixir_usec / 1_000, label: "elixir json diffing")
+  end
+end