NFC Authentication in your own App

const url = new URL( window.location );

// Tag ID was defined as the 1st slug in this example
const tagId = url.pathname.split('/')[1];
const eCode = url.searchParams.get('eCode');
const enc = url.searchParams.get('enc');
const cmac = url.searchParams.get('cmac');

const res = await fetch(
	'https://third-party.etrnl.app/v1/tags/verify-authenticity',
	{
		method: 'POST',
		headers: {
			'Content-Type': 'application/json',
			'API-KEY': 'XXXXXXX' // Your API key goes here
		},
		body: JSON.stringify({ tagId, eCode, enc, cmac })
	}
);

const {
	success, // boolean
	exists, // boolean
	authentic, // boolean
	ctr, // number
	uid, // string (only provided if using the private key)
	err // error code
} = await res.json();