The hottest tech IPO of the quarter, Atlassian, just had a big pop out of the gate

The IPO market may be cooling down for a lot of tech companies, but that doesn't seem to be the case with Atlassian, the business software maker best known for its Jira and HipChat products.

Atlassian began trading on Thursday at over $27 per share - up over 30% from the the starting price of $21.

At $27, the company is valued at around $5.6 billion. It's trading under the ticker "TEAM," referring to the team collaboration software it makes.

That's a nice boost from the price range Atlassian had originally projected, which would have given it a valuation of $3.8 billion at the high end.

It's a strong indicator of investor interest. And it means Atlassian could turn out to be the most successful tech IPO of the year, drawing solid interest from public investors. If all goes well when trading actually begins, Atlassian's market cap will end up well exceeding its private-market valuation, which was reported to be $3.3 billion in 2014.

Unlike a lot of the tech startups that are losing money, Atlassian has been profitable for the last 10 years and is still growing at a solid pace. It's also achieving its growth without spending too much on sales and marketing, typically the biggest expense item for most software companies.

Atlassian was founded in 2002, but it hasn't taken any outside investment. The last two funding rounds from Accel and T. Rowe Price were done to let employees sell some of their shares, and Atlassian says the cash wasn't used for operations.

Some of the most anticipated tech IPOs this year saw lower-than-expected interest from the public market, significantly cutting their value on their way to going public.

Square, for example, lost nearly half of its value when it went public earlier this month compared to the $6 billion valuation it got in the private market last year - though shares popped on the first day of trading. Box also saw its IPO price bring its market cap below its previous VC valuation when it went public earlier this year.