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Cloudflare Filters API

Cloudflare Filters is an API-only component of Firewall Rules for designing complex criteria that rely on boolean operators and other logic to examine incoming HTTP traffic and look for a match.

For example, a filter matching:

  • An HTTP user agent, and
  • The HTTP path, and
  • The source IP address

May be associated with a firewall rule declaring that the request should be blocked.

Use Rules Lists within a filter to refer collectively to a group of IP addresses. Refer to the Rules List API for more information.

Before getting started with the Cloudflare Filters API, familiarize yourself with Firewall Rules expressions. For a complete reference, see Firewall Rules language.

Differences from other Cloudflare APIs

The Firewall Rules API behaves differently from most Cloudflare APIs in two ways:

To get started, review What is a filter?, followed by the Cloudflare Filters JSON object and Endpoints.