How Can I Secure Transactions Made With Client-side Paypal Smart Checkout Buttons?

I'm trying to make a Smart Checkout button in my website which is currently running 100% in client-side. I pass an amount to the createOrder function, based on the contents of the

Solution 1:

Is there any way to make client-side PayPal Smart Checkout buttons, while also protecting myself from this kind of exploits?

This is why server-side verification is a must. It is very easy to exploit these kind of things client-side and you cannot secure it client side either. PayPal have documentation on server side implementations for verifying payments. They have many SDK's too to suit your needs. e.g. NodeJS, PHP, Python...

PayPal Checkout Server-Side SDK