The website is under development then use this plugin to display a coming soon page to your visitors. The plugin allows collecting all visitors subscriptions. When your site will live plugin notify all your active subscriber about site launch. Test plugin here as an admin.
Username is userdemo & password is userdemo
7+ Email News Latter APIs
Madmimi, Constant Contact, Mailchimp, Campaign Monitor, Aweber, GetResponse, WPMail, SMTP, and database newsletter Integrated