Customer.io is a customer engagement platform that uses first-party data to automate personalized messages across channels including email, SMS, push notifications, and in-app experiences. It targets tech-savvy organizations focused on scaling interactions through AI-driven insights and flexible workflows.

Core features include a visual workflow builder for drag-and-drop automation design, supporting triggers from events, segments, or dates. Omnichannel delivery ensures unified experiences, while the design studio offers code and no-code editors with Liquid personalization and AMP support. Data management handles unlimited sources via APIs, webhooks, and reverse ETL integrations with warehouses like Snowflake.

Analytics provide dashboards for metrics comparison, A/B and cohort testing for optimization, and AI-assisted segmentation to identify opportunities. Security complies with ISO 27001, GDPR, HIPAA, and SOC 2, with options for EU or US data residency. Pricing starts at $100 monthly for Essentials with 1M email sends, scales to custom Enterprise plans.

Competitors like Klaviyo excel in e-commerce specifics but offer less breadth in custom data objects, while Braze matches real-time capabilities at higher costs for mid-sized users. Recent G2 reviews praise integration ease and deliverability, averaging 4.6 stars from over 500 users.

Users appreciate robust event tracking and multi-channel support for complex campaigns, though some note a learning curve for advanced segmentation. Capterra feedback highlights strong support response times under 24 hours. For implementation, connect initial data sources during the 14-day trial to test a basic journey and monitor conversion goals.