With A Huge $70 Million Investment, Twilio Is Now Worth $500 Million

San Francisco-based startup Twilio just scored a $70 million Series D funding round and is moving steadily towards an IPO.

Twilio's core tech is a piece of software code called an application programming interface (API) that makes it easy for developers to add telephone calls and texting to websites and mobile apps.

A business could use Twilio to let a customer rep talk to people visiting its web site. Or a taxi service could use it to send an SMS message to customers letting them know what time their rides will arrive.

So far, Twilio has struck deals with more than 1,000 telecom carriers around the world. That's a big help because without a service like Twilio, developers would have to make their own deals with each carrier.

Twilio also sells some cloud services to businesses like a "virtual call center" that routes calls to the right people and records calls in the cloud.

With this latest round, Twilio has raised more than $100 million in VC funding and signed up more than 200,000 developers. It now has a valuation of about $500 million, GigaOm's Om Malik reports.

Next up is likely an IPO. While Twilio's cofounder and CEO Jeff Lawson wouldn't give a timeline, he told Greg Kumparak of Techcrunch an IPO would be “the next logical step.”