Squarespace founder Anthony Casalena said in a memo that the cuts would mostly affect product and engineering teams. Abbie Parr/Getty Images

Squarespace is laying off 19% of its staff in a move its CEO said would help it "adapt for the modern era" with leaner teams and "more player coaches."

The website-building software company is reducing its head count by about 300 employees, according to a companywide memo sent by Squarespace CEO Anthony Casalena on Monday.

Most of the cuts affect product and engineering teams, according to the memo, which was seen by Business Insider.

"The way we need to work is changing faster than at any point in our history, and our operating model must adapt for the modern era," wrote Casalena. "This means smaller teams, more player coaches, and a simplified organizational structure."

Affected staff will get a minimum of 16 weeks of base salary plus additional weeks based on tenure and benefits through May 2027.…