diff --git a/README.md b/README.md
index 5ded5bd..e0d78fe 100644
--- a/README.md
+++ b/README.md
@@ -45,6 +45,7 @@ Set your API key and client name in `config/application.rb`:
 ```ruby
 config.filestack_rails.api_key = "Your Filestack API Key"
 config.filestack_rails.client_name = "custom_client_name"
+config.filestack_rails.cname = "custom_cname"
 ```
 The client name defaults to "filestack_client" and is injected into your client-side Javascript. This is because v3 of the File Picker lives in the Javascript of your web application. For more information, please see our [File Picker documenation](https://www.filestack.com/docs/javascript-api/pick-v3).
 
diff --git a/app/helpers/filestack_rails/application_helper.rb b/app/helpers/filestack_rails/application_helper.rb
index 7f1bb06..30644c0 100644
--- a/app/helpers/filestack_rails/application_helper.rb
+++ b/app/helpers/filestack_rails/application_helper.rb
@@ -13,9 +13,9 @@ def filestack_js_init_tag
       signature, policy = get_policy_and_signature
       javascript_string = if policy && signature
                             "var #{client_name} = filestack.init('#{apikey}'," \
-                            "{'signature': '#{signature}', 'policy': '#{policy}'});"
+                            "{'signature': '#{signature}', 'policy': '#{policy}'}, '#{cname}');"
                           else
-                            "var #{client_name} = filestack.init('#{apikey}');"
+                            "var #{client_name} = filestack.init('#{apikey}', '', '#{cname}');"
                           end
       javascript_tag javascript_string
     end
@@ -46,6 +46,10 @@ def filestack_image(url, options = {})
 
     private
 
+    def cname
+      ::Rails.application.config.filestack_rails.cname
+    end
+
     def create_javascript_for_picker(callback, options)
       client_name, = get_client_and_api_key
       json_string = if options.nil?
diff --git a/lib/filestack_rails/configuration.rb b/lib/filestack_rails/configuration.rb
index 1edd780..80ae230 100644
--- a/lib/filestack_rails/configuration.rb
+++ b/lib/filestack_rails/configuration.rb
@@ -1,6 +1,6 @@
 module FilestackRails
   class Configuration
-    attr_accessor :api_key, :client_name, :secret_key, :security, :expiry, :app_secret
+    attr_accessor :api_key, :client_name, :secret_key, :security, :expiry, :app_secret, :cname
 
     def api_key
       @api_key or raise "Set config.filepicker_rails.api_key"
diff --git a/spec/lib/configuration_spec.rb b/spec/lib/configuration_spec.rb
index ad43db0..e0df73f 100644
--- a/spec/lib/configuration_spec.rb
+++ b/spec/lib/configuration_spec.rb
@@ -36,4 +36,15 @@
       expect(configuration.security.signature)
     end
   end
+
+  describe "#cname" do
+    it "has no cname" do
+      expect(configuration.cname).to be(nil)
+    end
+
+    it "has cname" do
+      configuration.cname = "fs.mycname.com"
+      expect(configuration.cname).to eq "fs.mycname.com"
+    end
+  end
 end