Sandbox model for loadFileURL allowingReadAccessTo — renderer process can only read files within the specified directory tree

How to load local HTML files in WKWebView on iOS and macOS

Since iOS 13, loading local HTML via WKWebView requires the purpose-built loadFileURL(_:allowingReadAccessTo:) API. This post covers the correct approach, how to handle inter-page navigation including the /nextPage sandbox trap, and when to use WKURLSchemeHandler for same-origin-sensitive apps.