ethereum-payment-system

A basic payment system for the Ethereum blockchain using TypeScript and Node.js

You can read more about this project in this article: https://codecapsule.com/2022/06/01/building-payment-system-ethereum/

Tested use cases

The following use cases and product flows have been tested.

A) User has no plans — show products as available for purchase

1. Connect and sign with wallet
2. Product page shows options to buy

B) User has a plan — show products as disabled

1. Connect and sign with wallet
2. Product page shows current plan, and options to buy are greyed out

C) User has a no plan — user buys product truthfully

1. Select product on product page
2. Click payment
3. Transaction is found by backend, plan is activated.
4. Access granted.

D) User has a no plan — user gets whitelisted

1. Select whitelist product on product page
2. Click payment
3. Whitelist is found by backend, plan is activated.
4. Access granted.

E) User has a no plan — user buys product and changes price when paying

This scenario is not testable via a wallet because there is no way to update the amount. However, an attacker could call the API programmatically and this test is here to ensure this cannot be exploited.

1. Select product on product page
2. Click payment
3. User changes value.
4. Transaction is found by backend, and rejected.
5. Access denied.

F) User with plan tries to buy while signed out

1. User is signed out.
2. User selects a plan and clicks buys
3. User should get rejected.
4. Transaction is not possible.

G) Plan expired — user loses access

1. User can access restricted page
2. Once “valid_until” date is met, the user loses access to that data.

MIT License - Copyright (c) 2022 Emmanuel Goossaert