Cloud communications firm Twilio (TWLO - Get Report) made its largest-ever acquisition this week, snapping up email marketing platform SendGrid (SEND) for $2 billion.

What's behind the blockbuster deal? Twilio CEO Jeff Lawson tells TheStreet that the deal fleshes out Twilio's existing portfolio of products -- which includes APIs for voice, chat, videoconferencing and more -- with an email product. Email is still a vital channel for businesses to talk to customers, and Lawson sees the acquisition as a way to make sure that Twilio has products across every single channel that a business would potentially use to reach customers.

Twilio's stock has been on a tear in 2018, up more than 200% since the beginning of this year, and Lawson has an ambitious plan to help drive a "communications Renaissance" for businesses, making it easier than ever to compete on great customer service. At its annual conference this week, Twilio will also roll out a new payments feature that allows businesses to security accept payment details during a call.

The multi-billion deal also merges two publicly traded companies. When the deal closes in early 2019, the acquisition will convert SendGrid to Twilio shares at a rate of 0.485 per share.

SendGrid is among the 5 Stocks to Buy for the Next Leg of the Nasdaq Rally written by Real Money's Timothy Collins

TheStreet's Annie Gaus caught up with Twilio CEO Jeff Lawson to talk about what the deal means for the fast-growing cloud communications firm.