US firm Twilio, which enables developers to build voice, video or messaging into their apps, raised a higher than anticipated $150 million via an initial public offering.

The firm, now valued at $1.2 billion, issued 10 million shares of Class A common stock at a price of $15.00 per share.  High profile customers include Uber and WhatsApp.

The shares will trade on the New York Stock Exchange.

According to the Wall Street Journal (WSJ), the IPO is priced above the $12 to $14 range the company was first targeting.

The report also said 17 per cent of Twilio’s revenue came from WhatsApp, although the app maker has no obligation to provide any notice to Twilio if it decides to top using its services, a potential risk to be weighed by investors.

Twilio’s website explains that it takes care of “the messy telecom hardware and exposes a globally available cloud API that developers can interact with to build intelligent and complex communications systems.”

For instance, developers can create multi-party video and HD audio experiences in apps or create mobile-friendly chat experiences with its SDKs and global real-time messaging infrastructure.

One of its clients is Uber and it allows passengers to contact their driver by connecting the app to the phone network.

In April, Twilio enabled developers to reach customers over Facebook Messenger, noting that “the integration with Messenger significantly reduces the development effort needed to build and maintain communications apps and experiences that can reach customers across multiple messaging channels.”