On the frontend, you want to use pre API hooks to modify the request object: https://supertokens.io/docs/emailpassword/advanced-customizations/frontend-hooks/pre-api Specifically, you want to modify the request object when the event

"EMAIL_PASSWORD_SIGN_IN"

is fired. You will want to add the appName to the request object, and then read that in the API code above (instead of doing

options.req.headers["origin"];

)