How to Detect Cluely?

One of the most common ways candidates cheat in virtual interviews today is through hidden overlays—applications (e.g., Cluely, InterviewCoder) that render answers or guidance on top of the screen while remaining invisible to the interview platform.

These overlays are especially difficult to detect because they operate outside the browser sandbox. Interview environments are typically hosted inside webpages, which means they have no direct visibility into what other applications are rendering on the user’s screen. As a result, traditional browser-based detection methods are fundamentally blind to this class of attacks.

To address this gap, we developed a hidden overlay detection algorithm designed specifically to identify cheating tools such as Cluley-style overlays.

Our approach does not rely on seeing the overlay directly. Instead, it leverages a set of side-channel signals—indirect indicators that overlays inevitably produce. These signals manifest as abnormal software and hardware behavior, including subtle inconsistencies in rendering, input handling, and system-level interactions.

By continuously collecting and correlating these signals, our algorithm is able to:

• Detect the presence of a hidden overlay
• Accurately pinpoint its location on the screen
• Build a spatial map indicating where the overlay is being rendered

This signal accumulation allows us to infer what the browser cannot observe directly, effectively breaking out of the limitations imposed by the browser sandbox—without violating it.

Overlay detection is just one of several algorithms we’ve developed to combat cheating in virtual interviews. Together, these systems enable robust, real-time detection of sophisticated cheating techniques that are increasingly common and increasingly hard to spot.

If you’re interested in trying out cheating detection platform for yoursel, feel free to schedule time .