diff --git a/lib/sinatra/browserid.rb b/lib/sinatra/browserid.rb
index 39ba9b1..8b10f78 100644
--- a/lib/sinatra/browserid.rb
+++ b/lib/sinatra/browserid.rb
@@ -86,12 +86,11 @@ def self.registered(app)
           "audience" => audience,
         }
         data_str = data.collect { |k, v| "#{k}=#{v}" }.join("&")
-        res, body = http.post("/verify", data_str)
+        res = http.post("/verify", data_str)
 
-        # TODO: check res is a 200
-        verify = JSON.parse(body) || nil
-        if verify.nil?
-          # JSON parsing error
+        if res.code =~ /^2\d{2}$/
+          verify = ::JSON.parse(res.body)
+        else
           return
         end