Twilio, the closely-watched tech IPO, is already beating Wall Street expectations

San Francisco-based Twilio, which provides phone and text message services to app developers, has priced its much-anticipated IPO at $15 per share.

At $15 per share, Twilio is now valued at $1.23 billion, beating the company's last private valuation of $1 billion.

Twilio had previously said it expected to price the offering between $12 and $14 per share, so it's already exceeding expecations.

Silicon Valley is watching this deal closely: Twilio is the second overall tech IPO of the year, and the first so-called "unicorn" startup with a private valuation of $1 billion to go public so far in 2016. Investors will be reading the tea leaves.

Twilio is offering 10,000,000 shares for sale in this IPO, meaning they've raised $150 million. Shares of Twilio are expected to begin trading on the New York Stock Exchange on Thursday under the ticker TWLO.

Founded in 2008, Twilio has raised $233 million in venture capital in its lifetime, from investors including Salesforce Ventures, Amazon, and Chris Sacca's Lowercase Capital. Twilio had most recently raised $130 million at $11.31 a share in a July 2015 round led by T. Rowe Price.