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.

Deprecation notice

Firewall rules have been deprecated. Cloudflare has moved existing firewall rules to WAF custom rules. For more information on this change, refer to the migration guide.

For example, a filter matching:

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

Associate a filter with a firewall rule to define the scope of that rule.

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

Before getting started with the Cloudflare Filters API, familiarize yourself with rule expressions. For a complete reference, refer to Rules language.

Differences from other Cloudflare APIs

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

• API calls accept and return multiple items, and allow applying data changes to multiple items.
• Although API calls return the standard response, the error object follows the JSON API standard ↗, such that in an error condition, it is clear which item produced the error and why.

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