Application performance monitoring (APM) startup AppDynamics, which built up a valuation well into unicorn territory, filed for its IPO on Dec. 28.

Founded in 2008, the company has raised $315 million, including a $158 million round that closed about a year ago. Reuters reported that the round pushed AppDynamics' valuation to $1.9 billion.

AppDynamics seeds an on-premises or cloud environment with agents that track user interactions and determine what a normal level of application performance would be. From there, the software ought to be able to detect performance deviations in real time. The company's main competitors in APM are Dynatrace and New Relic, as noted in the SDxCentral report, Network Performance Management Takes On Applications. Among larger companies, AppDynamics’ prospectus lists BMC and CA Technologies as competitors.

AppDynamics has been growing quickly but is still losing money. For the fiscal year ended January 31, 2016, AppDynamics reported revenues of $151 million, but it reported net losses of $134 million, or $4.85 per share.

For the previous year, which ended January 31, 2015, the company reported revenues of $82 million and losses of $94 million, or $3.96 per share.

For the quarter ended Oct. 31, the company reported revenues of $60.3 million and net losses of $26.4 million; the company's prospectus doesn't spell out per-share losses for the period.

The company's largest shareholders are Greylock Partners and Lightspeed Venture Partners. Each holds 22.7 million shares, a 20.8 percent stake in the company.