While many old Flash-based tools are defunct, a new generation of HTML5/WebAssembly tools has emerged.
Reputable online patchers process files . Files are read locally using the browser's File API and never transmitted to external servers. As PokeHackZone states: "Patching is done locally or via trusted third-party tools, and no files are stored on our servers". Before using any online patcher, verify its privacy policy or review its source code if open-source.