Set up and modules - Diem

Set up the Diem Reference Merchant project

To set up your environment or deploy the Diem Reference Merchant project, refer to the latest information here.

The Diem Reference Merchant is available as a web application. All web UI resources can also be found here.

Merchant front-end module

The merchant front-end module demonstrates the merchant’s online store UI. It communicates with the merchant back-end and the VASP module to carry out its commands.

Name	Description
Implementation	The Merchant front-end is a React app written in TypeScript.
Extend functionality	Use a robust e-commerce solution for a reliable online store implementation.

Merchant back-end module

The Merchant back-end is a service performing all the product management and payment operations for the merchant front-end.

Name	Description
Implementation	The merchant back-end module is implemented in Python, manifesting a RESTful API using Flask.
Extend Functionality	The merchant back-end would usually be a part of a complete e-commerce solution, together with the front-end.

VASP module

The VASP module is an autonomous service that performs all the Diem-related operations for the merchant back-end and front-end modules.

Name	Description
Implementation	The VASP module is implemented in Python, manifesting a RESTful API using Flask; it uses Postgresql for data persistence.
Extend functionality	The proposed VASP reference implementation is centered on serving an online retailer. However, VASPs could supply a wide range of services, including wallets, liquidity, trading, and more.

Localization

The UI is fully translatable using standard React i18n library react-i18next. All texts are mapped in JSON files located at front-end/src/locales/LANGUAGE.

To generate new translations, a script is available to auto-generate new translations using a third-party translation service or to export all existing text into a CSV file for manual translation.

Located at scripts/generate_i18n.py are usage examples for translating from English to Spanish. ./scripts/generate_i18n.py -s en -d es -a will use EN JSON files located at front-end/src/locales/en and generate new JSON files at front-end/src/locales/es.

Instructions for using the newly generated files will be shown upon completing these steps:

Add import ES from "./es"; to front-end/src/locales/index.ts
Add es: ES; to the default Resource object in there

To extract translations into a CSV file for manual translations, you can use the export flag: ./scripts/generate_i18n.py -s en -d es -e ./english_texts.csv To import manually translated CSV you can use the import flag: ./scripts/generate_i18n.py -s en -d es -i ./english_texts.csv

Use cases

Direct payment under US$1,000

In this use case, the user pays for a product using Diem Coins from his wallet directly to the Regulated VASP. Since no additional verification is required for amounts under US$1,000, the user wallet posts the transaction directly to the Diem Blockchain. The merchant settles the payment later using the payout procedure.

Payment payout

Payout is a procedure between a merchant and its payment VASP. Payout causes the funds collected from a client by the VASP for some previous purchase, to be transferred to the merchant in the form of a fiat deposit to the merchant’s bank account. The VASP employs a liquidity provider (as an external service) to convert Diem funds to a fiat currency.

Paid out payments are not refundable.

Notice that the Diem Reference Merchant does not demonstrate the final fiat transfer and focuses only on the Diem operations.

Payment refund

Refund is an operation triggered by the merchant that returns the payment to its origin. The operation creates a new blockchain transaction in the opposite direction from the original payment transaction.