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:
- a 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.
Currently, Cloudflare Filters in an API-only feature and lacks a graphical user interface.
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:
- 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.