Patcher
Turn your Japanese ROM into the English one, right here. Choose the ROM file, or the .zip it came in. The page recognises the game, applies the patch, and saves the English ROM. Have a patch from somewhere else? It applies those too, for any game.
Your ROM stays on your device. The patching happens in this browser and nothing is uploaded.
How it works
Everything happens in your browser. Your ROM is never uploaded: the page downloads only the patch file from this site and saves the English ROM straight to your device. Your original file isn't changed.
I don't host ROMs or link to them. Use a dump of your own cartridge.
It also applies patches from elsewhere, for any game on any system: if your ROM isn't one I translate, it asks for the patch file, and with one of mine you can use your own instead. It reads BPS, IPS and UPS. BPS and UPS patches record the ROM they're for, so a wrong ROM is caught before anything is written; IPS patches don't, so check the patch's notes for the ROM it needs.
Prefer another patcher? Each game's page has its BPS file on GitHub. ROM Patcher JS, Floating IPS, and beat all apply it the same way.