Twilio, the ubiquitous communications platform, today announced its plan to acquire the API-centric email platform SendGrid for about $2 billion in an all-stock transaction. That’s Twilio’s largest acquisition to date, but also one that makes a lot of sense given that both companies aim to make building communications platforms easier for developers.

“The two companies share the same vision, the same model, and the same values,” said Twilio co-founder and CEO Jeff Lawson in today’s announcement. “We believe this is a once-in-a-lifetime opportunity to bring together the two leading developer-focused communications platforms to create the unquestioned platform of choice for all companies looking to transform their customer engagement.”

SendGrid will become a wholly owned subsidiary of Twilio and its common stock will be converted into Twilio stock. The companies expect the acquisition to close in the first half of 2019, after it has been cleared by the authorities.

Twilio’s current focus is on omnichannel communication, and email is obviously a major part of that. And while it offers plenty of services around voice, video and chat, email hasn’t been on its radar in the same way. This acquisition now allows it to quickly build up expertise in this area and expand its services there.

SendGrid went public in 2017. At the time, it priced its stock at $16. Today, before the announcement, the company was trading at just under $31, though that price obviously spiked after the announcement went public. That’s still down from a high of more than $36.5 last month, but that’s in line with the overall movement of the market in recent weeks.

Today’s announcement comes shortly before Twilio’s annual developer conference, so I expect we’ll hear a lot more about its plans for SendGrid later this week.

We asked Twilio for more details about its plans for SendGrid after the acquisition closes. We’ll update this post once we hear more.