OneSignal is customer engagement software that specializes in push notifications, SMS, email and in-app messaging. It's fast and reliable and works for different platforms including Shopify and WordPress.
OneSignal has a variety of features to take communication to the next level and ensure that customers are engaged and responsive. They include personalization and segmentation, rich media, analytics and A/B testing.
The software has a push notification preview tool that lets you see what your message will look like on desktop, mobile, android and iOS. You don't have to buy the software to test this feature; it's available for free on the website.