Certificate Transparency is a project started by Google to increase the accountability of the WebPKI by creating public repositories, run by various organizations, containing all the publicly-trusted certificates that are being issued. This allows website owners to find all the certificates that have been issued for their website, and see that no certificates have been issued without their approval. Finding mis-issued certificates is so important because they can allow malicious actors to attack a website's customers.

A big barrier to getting more people to run Certificate Transparency Logs is that they can be very expensive to run. This project uses Workers in a carefully considered way to dramatically reduce the total cost of operation. A full explanation is available in the “Cost Analysis” page in the docs folder.