A Fake Door Test measures demand for a feature or product that does not yet exist. The method works by presenting users with an offering — such as a button, a menu item, or a landing page — and then measuring how many actually click or sign up. The key: there is nothing behind the door. Instead, an explanation appears stating that the feature is in development.
For example, a product team is considering whether to build an export feature. Instead of investing weeks in development, an “Export Data” button is added to the interface. Users who click it see a message: “This feature is in progress — would you like to be notified?” The click rate reveals whether real demand exists. If it falls below one percent, the answer is clear — without a single line of production code being written. It is important that the test communicates fairly: users should not be left frustrated.
The Fake Door Test is one of the leanest experiments in the Lean Startup repertoire. It is especially suited for feature prioritization and answers the most fundamental question of all: Does anyone actually want this?
