That would more than double the valuation that HeadSpin received in a funding round last year.
Final terms and details of the Series C financing haven't been announced and are subject to change, but the filing indicates the deal would raise as much as $75 million. Representatives of HeadSpin, based in Palo Alto, didn't immediately respond to a request for comment.
Backed by investors including Battery Ventures, GV and Iconiq Capital, HeadSpin's valuation leaped to $510 million in a round last year. The company has previously raised an estimated $31 million since it was founded in 2015.
Customers of HeadSpin use its technology to test and monitor apps in real time to shorten their product-release cycles. The company has listed Tinder, DocuSign, Pinterest and Airbnb among its customers.
Co-founder and CEO Manish Lachwani previously co-founded Appurify, a platform for software developers to test apps and websites. Google acquired Appurify in 2014.
HeadSpin's advisory board consists of business-software veterans Cloudera CEO Tom Reilly, AppDynamics founder Jyoti Bansal, and BV Jagadeesh, founder of Exodus and NetScaler.
Other players in the app-testing industry include Amazon's AWS Device Farm and Google's Test Lab, which both focus on automated performance tests.
Featured image via Unsplash.