Human resources (HR) technology platform Justworks has raised $40 million in a series D round of funding led by FirstMark Capital, with participation from Index Ventures, Thrive Capital, Bain Capital, and Redpoint Ventures.

Founded out of New York in 2012, Justworks serves as an online platform for businesses to manage their HR, payroll, benefits, and compliance procedures.

Above: Justworks: Choose a dental plan

Prior to now, Justworks had raised $53 million, and with another $40 million in the bank it said that it plans to invest in its “ongoing market expansion and product innovation,” according to a statement issued by the company.

“This funding is a major milestone for Justworks, and further proof of our accelerated success in our mission to give entrepreneurs and their teams the support and peace of mind to work fearlessly,” noted Justworks founder and CEO Isaac Oates. “As we look to this next stage, we are excited to build on the achievements and innovation of the past five years to continue to meet the needs of modern business leaders and their teams.”

Above: Justworks CEO and founder Isaac Oates

Justworks’ competitors include the well-funded but controversy-mired Zenefits, which has raised around $600 million, and Gusto, which has raised nearly $200 million all-in.

FirstMark Capital, which has backed big-name companies such as Pinterest, Airbnb, Shopify, and DraftKings, clearly sees a big market for HR tech.

“As a former operator, I admire the system Justworks has built to eliminate the pain points and connect a fragmented HR industry,” added FirstMark Capital managing director Beth Ferreira. “And I’m not the only one. Justworks has built a substantial business, and they have only just scratched the surface of the products and services that they can offer.”

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