Castle's technology helps prevent account takeover (ATO) attempts, whether they employ manual or automated methods, including credential stuffing. :
Castle, a San Francisco-based startup that wants to help businesses keep their customers’ online accounts safe from fraud, has raised $9.2 million in a series A round of funding from Index Ventures, with participation from Y Combinator, First Round Capital, F-Prime Capital Partners, and a host of individual angel investors. Founded in 2015, Castle works with web and app developers looking to offer greater security inside their consumer-facing apps.