Challenges - Precursor introduces session-based bot detection

Mon, 13 Jul 2026 00:00:00 GMT

Precursor is rolling out to all customers starting today. Precursor is client-side JavaScript that enables session-based bot detection.

You can read the announcement blog for background on why we built Precursor and how session-level behavioral detection works.

With Precursor enabled, Cloudflare can:

Continuously evaluate behavioral signals across a session
Re-validate challenge clearance as behavior changes
Update bot scores with session context
Provide client-side visibility where none previously existed

It integrates with existing protections, including Security Rules, and can be enabled directly from the Cloudflare dashboard with configurable modes to balance security and user experience.

To learn more, refer to the Precursor documentation.

Cloudflare changelogs | Challenges

Challenges - Precursor introduces session-based bot detection