The round was led by Accel with participation from existing investor Summit Partners. The new financing brings Klaviyo's total funding to date to $358.5 million. The investment will help further fuel Klaviyo's rapid growth through R&D, hiring, increased sales, customer support and international expansion. The company also announced it has added Accel's Ping Li to its board.

Klaviyo, founded in 2012, was bootstrapped for three years before taking outside funding and is profitable. The company raised just $8.5M in outside investment before it closed a $150M Series B round last March led by Summit Partners. The new capital from Accel and Summit Partners will help accelerate growth and enable Klaviyo to remain focused on bolstering its best-in-class customer support and building out the platform's AI and machine learning capabilities to engineer and design the future of guided software.

Klaviyo is a world leading owned marketing platform dedicated to accelerating revenue for online businesses. Klaviyo makes it easy to store, access, analyze and use transactional and behavioral data to power highly-targeted customer and prospect communications. Over 50,000 innovative companies like Unilever, Custom Ink, and Huckberry sell more with Klaviyo. Learn more at www.klaviyo.com.