rom hex editor — free browser tool | fatcousin

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view and edit rom bytes in hex · navigate by offset · search byte patterns · export modified rom · runs locally

drop rom

drop any rom or binary file

no size limit — large files load read-only until edited

Select file

status

drop a rom to view and edit its bytes

notice

you supply your own files. fatcousin does not host, link to, or recommend sources for rom files, bios files, or copyrighted game data. this tool is for preservation, modding, research, and education with files you lawfully possess. all processing runs in your browser — files never leave your device.