cf.worker.upstream_zone
cf.worker.upstream_zone String Identifies whether a request comes from a worker or not.
When a request comes from a worker, this field will hold the name of the zone for that worker. Otherwise, cf.worker.upstream_zone is empty.
 Categories: 
   - Request
 
Was this helpful?
- Resources
 - API
 - New to Cloudflare?
 - Products
 - Sponsorships
 - Open Source
 
- Support
 - Help Center
 - System Status
 - Compliance
 - GDPR
 
- Company
 - cloudflare.com
 - Our team
 - Careers
 
- 2025 Cloudflare, Inc.
 - Privacy Policy
 - Terms of Use
 - Report Security Issues
 - Trademark