Can I take credit card payments using the TGX graphql API all on the front end?

Below is an example frontend app built in Angular using an API Key to perform bookings. Can you confirm if we can do the same or is that company using the API Key incorrectly?

GitHub - travelgateX/hotelX-angular-sample Our goal is to take credit card payments from the front end through the TGX graphql apis.

That is we may not have a backend involved at all. Is there an issue with that like security or otherwise?

Also can you tell us more about HotelPay-X | Credit card data storage and payment solutions for any hotel ? The link to doesnโ€™t appear to work anymore.