Question: I need a system that can provide customizable customer notifications and reminders for subscription renewals and updates.

One promising option is Courier, a notification API that lets developers send messages through a variety of channels, including email, SMS and push notifications, with a single API. It connects to more than 50 providers and offers SDKs for several programming languages. Courier's features include customizable UI components, sophisticated user preferences and automations, making it a good option for businesses trying to modernize their notifications and keep customers engaged.

Another good option is Rainex, a billing and subscription management system. Rainex automates and simplifies recurring revenue processes, including subscription management, automated recurring billing and customer notifications. The system works in many industries and includes a customer portal and payment gateway integrations, so it can be a good option for subscription-based businesses trying to keep customers happy.

If you're looking for a system to help you retain and grow customers, Reteno is worth a look. It offers personalized omnichannel engagement across eight notification channels and is designed to be easy to integrate and automate. Reteno's event-driven campaigns and segmentation tools let you target specific groups of users, so it can be good for turning inactive users into active customers. It's a no-code system, so marketers can design and execute their own campaigns.