diff --git a/app/helpers/external/mailbluster_helper.rb b/app/helpers/external/mailbluster_helper.rb
new file mode 100644
index 00000000..2f57fa26
--- /dev/null
+++ b/app/helpers/external/mailbluster_helper.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module External
+  module Mailbluster
+    def create_lead(user)
+      # TODO
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/helpers/external/mailbluster_helper_spec.rb b/spec/helpers/external/mailbluster_helper_spec.rb
new file mode 100644
index 00000000..b6d3016e
--- /dev/null
+++ b/spec/helpers/external/mailbluster_helper_spec.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'webmock/rspec'
+
+describe MailblusterHelper, type: :helper do
+  let!(:user) { create(:user) }
+
+  describe 'create_lead' do
+    it 'makes a post request to Mailbluster\'s API' do
+      create_lead(@user)
+      expect(WebMock).to have_requested(:post, "api.mailbluster.com/api/leads").
+        with { |req| req.body == "abc" }
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 2d680fb2..32fc961c 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -12,6 +12,10 @@ SimpleCov.start 'rails'
 ENV['RAILS_ENV'] ||= 'test'
 require File.expand_path('../../config/environment', __FILE__)
 
+# Prevent tests from making calls to the Internet
+require 'webmock/rspec'
+WebMock.disable_net_connect!(allow_localhost: true)
+
 require 'rspec/rails'
 require 'shoulda/matchers'
 require 'webdrivers'