If email is on the way out, the investors who have just ponied up $20.7 million to email delivery platform SendGrid apparently haven’t gotten the message.

The C round funding, announced today, was raised from Bain Capital Ventures and previous investors Bessemer Venture Partners and Foundry Group. It brings the total raised by the company to $48 million.

“Email will remain the standard for online B2B and B2C communication,” newly appointed CEO Sameer Dholakia told VentureBeat, “despite the rise in person-to-person messaging alternatives.”

“Think about all the email [companies] want, [like] payment receipts, password resets, social notifications,” he said. “Brands such as Uber, Pinterest, LinkedIn all rely on email to engage with their users at the most critical moments [and] users can’t actually sign up for any of these services without email. ”

He added that SendGrid’s developer-oriented platform, which sends more than 435 million emails daily, is used by about a third of Alexa’s top 10,000 Web sites that employ a transactional email provider.

The new money will be used to expand the platform, Dholakia said, such as building new data-driven products, boosting marketing efforts to add more customers, and investing in ways to increase email deliverability.

Efficient email delivery is one of the key differentiators for the Boulder, Colorado-based company, Dholakia told us, given that an estimated one-fifth of company-sent emails don’t reach a recipient’s inbox. The company prides itself on a 30-plus-person internal team that is focused on deliverability, in part by working with major email providers.

Amazon Simple Email Service (SES) is the main competitor, he said, along with ten other smaller outfits. SendGrid said its other main competitive advantages include 24/7 customer service support and a self-serve model that keeps costs low for adding customers beyond its current base of over 180,000.