Case Study: Klaviyo achieves 99.94% email deliverability and scalable email & SMS at 10B/month with Twilio (SendGrid & Programmable Messaging)

How Klaviyo helps retail businesses build deep connections with customers

Klaviyo is a marketing platform that helps retail brands build personalized relationships with customers across email, SMS, and social channels. As it scaled, Klaviyo needed to simplify the complexities of reliable message delivery, support a diverse customer base, and give developers flexible APIs so teams could focus on product innovation rather than infrastructure.

Klaviyo built its email platform on Twilio SendGrid’s Email API and its SMS offering on Twilio’s Programmable Messaging, enabling programmatic control, two-way texting, and self-serve onboarding. The results: average delivery rates of 99.94%, roughly 10 billion emails sent per month with fast delivery, strong benchmark metrics for welcome series (opens ~46.9%, clicks ~9.2%, conversions ~2.4%), rapid SMS growth, and improved customer insights via webhooks—allowing Klaviyo to concentrate on features and earn high customer satisfaction.

Klaviyo

Andrea Wan

Head of SMS