Content moderation does not and cannot work in a vacuum. Without transparent rules that online platforms can be held accountable for, many communities that host user-generated content would simply fail. CDT works to ensure that policies are accessible to users, that companies and governments protect and respect user rights, and that platforms have mechanisms in place to offer meaningful opportunities for appeal and redress. Along with partners in civil society and academia, we drafted the Santa Clara Principles on Transparency and Accountability in Content Moderation, a set of best practices for online platforms that host user-generated content. In the short time since they were published, the Santa Clara Principles — along with CDT’s larger body of related work — have become central to conversations happening on the Hill, in Silicon Valley, and in Europe concerning content moderation.