Klaviyo has raised $200 million in a round led by Accel, with participation from existing backer Summit Partners. The deal values Klaviyo at $4.15 billion, according to TechCrunch. The Boston-based company is a developer of customer data and marketing software that integrates with ecommerce platforms including Shopify and Stripe. Klaviyo has now raised $358.5 million in total private funding since it was founded in 2012. Accel partner Ping Li will join the company's board.