Customer.io Lifecycle System. 500k+ Monthly Messages

The brief wasn't "send better emails." It was to build an automation infrastructure capable of moving hundreds of thousands of users through a complete lifecycle , from first action to paid conversion to long-term retention, without breaking as the platform scaled.

82 concurrent lifecycle campaigns running in production simultaneously, built and managed inside Customer.io across 7 delivery channels: email, push, webhook, Slack, in-app, SMS, and browser. Every campaign tied to a specific user behaviour, a document published, an upload completed, a trial started, triggering the right message at the right moment without manual intervention.

The system covers every stage of the funnel: multi-cohort onboarding sequences for university students and content contributors, mid-funnel engagement campaigns for active users, monetisation flows converting free users to Premium, and re-engagement campaigns for users going dormant.

Alongside the campaign layer, I built out the full Design Studio, 1,158 email templates with dynamic personalisation using Liquid logic, A/B test frameworks across subject lines and send times, and a broadcast infrastructure now supporting 3,100+ newsletter campaigns.

— 5.15M+ messages delivered through the onboarding system alone — 30–38% open rates on core engagement campaigns (industry average: 20%) — 61.4% conversion rate on the Premium upgrade campaign — 505,035 messages sent from a single behaviour-triggered campaign — 48.7% open rate on broadcast newsletters at 31k+ recipients

This is not a campaign. It's infrastructure, the kind that earns revenue every hour, with or without anyone actively running it.