This plugin caches 404 error pages for websites, preventing performance degradation caused by floods of requests to non-existent URLs. It is designed for site administrators and developers who need to maintain server stability and page speed under heavy or malicious traffic.

• Full Page Caching for 404s: Serves a fully cached 404 page from an external object cache (like Redis or Memcached) to anonymous visitors, bypassing normal page processing.
• Dual-Cache Strategy: Implements both a regular cache and a longer-lasting stale cache to minimize the chance of a cache miss and ensure a page is always available to serve.
• Automatic Cache Generation: Creates the initial cached 404 page via a guaranteed invalid URI and refreshes it automatically using a scheduled task.
• Performance Header: Adds an X-WP-404-Cache header to responses, allowing developers to monitor whether a request was a cache hit or miss.
• Analytics Compatibility: Ensures the cached page reflects the originally requested URI, not the internal 404 generator, so visitor tracking remains accurate.