The Washington Post Fact Checker is a rigorous, transparent, non-partisan, fair and clearly written site. In my view, the Fact Checker clearly complies with the IFCN principles, even listing them at the bottom of fact checks.
The site conducts regular fact checks of those in or seeking political power. The Fact Checker clearly articulates its ratings system, sources, corrections policy, ownership and editorial structure and contact information. I recommend that the site provide more detailed biographies of all the reporters for the site so that the audience can have a more comprehensive picture of who is conducting the fact checks produced the Washington Post Fact Checker.