Customer.io

Customer.io is an event-driven lifecycle messaging platform for email, push, SMS, and in-app, built on real-time customer data with advanced segmentation, visual workflows, and AI-assisted insights.

Customer.io targets teams that need messaging driven by user behavior rather than static lists. By ingesting events and attributes in real time, it lets marketers and product teams build automated workflows that trigger the right message at the right moment across email, push, SMS, and in-app channels. The platform is known for powerful segmentation, a visual workflow builder, and flexibility that suits SaaS and product-led growth companies. Its AI additions help surface opportunities, streamline campaign creation, and optimize sends while keeping marketers in control of messaging. Pricing is based on the number of profiles stored rather than emails sent, starting at a higher entry point than basic email tools, which reflects its positioning as a serious lifecycle-messaging system. For companies with rich behavioral data, it is a leading choice, but it is more than small senders typically need.