XML-RPC is enabled by default since WordPress version 3.5 and allows communication between WordPress and other systems. If XML-RPC is disabled, any services relying on it will no longer work as expected.
Most of Jetpack’s features rely on the XML-RPC connection, and disabling XML-RPC would negatively affect:
- Security monitoring: Jetpack is one of several tools that monitor potential security issues in code.
- Uptime monitoring: Jetpack provides uptime monitoring for launched sites as part of VIP’s infrastructure alerting.
- Jetpack sync: Jetpack features that rely on a working XML-RPC connection would no longer will work properly, including site stats, Jetpack related posts, and Jetpack Activity Log.
- Jetpack Instant Search: Jetpack’s Elasticsearch solution increases search result speed and relevancy. If XML-RPC is disabled, Elasticsearch will not be reachable. Slow queries that would usually be offloaded to Elasticsearch will instead go directly to MySQL, which can cause performance issues.
VIP has multiple security protections in place to protect against unauthorized access and abuse of the XML-RPC endpoint.