Customer.io is a messaging automation platform built for tech-savvy marketing teams that need fine-grained control over customer communications. Colin Nederkoorn and John Allison founded it in 2012 in Portland, Oregon, with the philosophy that marketers should have the same flexibility as developers when building triggered campaigns.
The platform specializes in event-driven messaging. Instead of just “send an email to this segment,” Customer.io lets you trigger messages based on specific user actions — a feature used, a subscription upgraded, an item abandoned in a cart, a milestone reached. These event triggers connect to complex workflow automations that span email, push notifications, SMS, in-app messages, and webhooks.
Customer.io’s visual workflow builder supports branching logic, time delays, A/B testing within workflows, and conditional filters based on any attribute or event in your customer data. The platform also supports Liquid templating, giving marketers the ability to create highly personalized messages using the same templating language Shopify popularized.
The data layer sets Customer.io apart from simpler email tools. It accepts data via API, JavaScript snippets, or integrations with data warehouses and CDPs like Segment. You can import any customer attribute or behavioral event and use it immediately in segmentation and triggers, without waiting for a nightly sync.
The company is bootstrapped and profitable, serving over 7,500 companies including Notion, Shutterstock, and Frame.io. Pricing starts at $100/month for the Essentials plan. Customer.io positions itself between general email platforms like Mailchimp and enterprise marketing clouds like Braze — more technical flexibility than the former, simpler implementation than the latter.
