With the new Precursor technology, Cloudflare aims to continuously analyze and measure website visitor behavior to block automated bots.
Cloudflare has made Precursor generally available, a new technology that no longer checks bots just once when opening a website, but analyzes their behavior throughout the entire browser session. With this, the company aims to eventually make traditional CAPTCHAs obsolete.
According to Cloudflare, approximately 57 percent of all internet traffic now consists of automated bots. As a result, a one-time check when visiting a website is increasingly insufficient, as advanced bots can easily bypass those checks.
Behavior during full session
Precursor works directly in the visitor’s browser. A small script continuously collects signals about browsing behavior and sends them to Cloudflare’s edge servers, where they are analyzed in real-time. The technology looks at mouse movements, scrolling behavior, typing speed, clipboard usage, and how long a webpage remains visible in the browser. It does not store the entered characters themselves, but only the rhythm and timing of the interactions.
Cloudflare then checks whether that behavior is logical. For example, the system can determine that a user is moving the mouse according to the data while the browser window is inactive, or that typing is occurring while no text field is selected. Such contradictions increase the likelihood that it is an automated script.
Continuous bot score
Unlike traditional CAPTCHAs, Precursor does not assess visitors just once, but builds a dynamic bot score throughout the entire session. This score is maintained as a user navigates through a website or web application. As a result, bots can no longer cover their tracks by simply refreshing a page. With traditional checks, the assessment started over after a refresh, whereas Precursor continues to monitor the entire session.
According to CTO Dane Knecht, this is comparable to the difference between checking someone once at the entrance or observing their behavior throughout the entire visit. Cloudflare has not released any information regarding the price of Precursor.