Nostr Diagon Alley protocol (for resilient marketplaces)

Original protocol https://github.com/lnbits/Diagon-Alley

The concepts around resilience in Diagon Alley helped influence the creation of the NOSTR protocol, now we get to build Diagon Alley on NOSTR!

In Diagon Alley, merchant and customer communicate via NOSTR relays, so loss of money, product information, and reputation become far less likely if attacked.

A merchant and customer both have a NOSTR key-pair that are used to sign notes and subscribe to events.

For further information about NOSTR, see https://github.com/nostr-protocol/nostr

Terms

• merchant - seller of products with NOSTR key-pair
• customer - buyer of products with NOSTR key-pair
• product - item for sale by the merchant
• stall - list of products controlled by merchant (a merchant can have multiple stalls)
• marketplace - clientside software for searching stalls and purchasing products

Diagon Alley Clients

Merchant admin

Where the merchant creates, updates and deletes stalls and products, as well as where they manage sales, payments and communication with customers.

The merchant admin software can be purely clientside, but for convenience and uptime, implementations will likely have a server listening for NOSTR events.

Marketplace

Marketplace software should be entirely clientside, either as a stand-alone app, or as a purely frontend webpage. A customer subscribes to different merchant NOSTR public keys, and those merchants stalls and products become listed and searchable. The marketplace client is like any other ecommerce site, with basket and checkout. Marketplaces may also wish to include a customer support area for direct message communication with merchants.

Merchant publishing/updating products (event)

NIP-01 https://github.com/nostr-protocol/nips/blob/master/01.md uses the basic NOSTR event type.

The merchant event that publishes and updates product lists

The below json goes in content of NIP-01.

Data from newer events should replace data from older events.

action types (used to indicate changes):

• update element has changed
• delete element should be deleted
• suspend element is suspended
• unsuspend element is unsuspended

{
    "name": <String, name of merchant>,
    "description": <String, description of merchant>,
    "currency": <Str, currency used>,
    "action": <String, optional action>,
    "shipping": [
        {
            "id": <String, UUID derived from stall ID>,
            "zones": <String, CSV of countries/zones>,
            "price": <int, cost>,
        },
        {
            "id": <String, UUID derived from stall ID>,
            "zones": <String, CSV of countries/zones>,
            "price": <int, cost>,
        },
        {
            "id": <String, UUID derived from stall ID>,
            "zones": <String, CSV of countries/zones>,
            "price": <int, cost>,
        }
    ],
    "stalls": [
        {
            "id": <UUID derived from merchant public-key>,
            "name": <String, stall name>,
            "description": <String, stall description>,
            "categories": <String, CSV of voluntary categories>,
            "shipping": <String, CSV of shipping ids>,
            "action": <String, optional action>,
            "products": [
                {
                    "id": <String, UUID derived from stall ID>,
                    "name": <String, name of product>,
                    "description": <String, product description>,
                    "categories": <String, CSV of voluntary categories>,
                    "amount": <Int, number of units>,
                    "price": <Int, cost per unit>,
                    "images": [
                        {
                            "id": <String, UUID derived from product ID>,
                            "name": <String, image name>,
                            "link": <String, URL or BASE64>
                        }
                    ],
                    "action": <String, optional action>,
                },
                {
                    "id": <String, UUID derived from stall ID>,
                    "name": <String, name of product>,
                    "description": <String, product description>,
                    "categories": <String, CSV of voluntary categories>,
                    "amount": <Int, number of units>,
                    "price": <Int, cost per unit>,
                    "images": [
                        {
                            "id": <String, UUID derived from product ID>,
                            "name": <String, image name>,
                            "link": <String, URL or BASE64>
                        },
                        {
                            "id": <String, UUID derived from product ID>,
                            "name": <String, image name>,
                            "link": <String, URL or BASE64>
                        }
                    ],
                    "action": <String, optional action>,
                },
            ]
        },
        {
            "id": <UUID derived from merchant public_key>,
            "name": <String, stall name>,
            "description": <String, stall description>,
            "categories": <String, CSV of voluntary categories>,
            "shipping": <String, CSV of shipping ids>,
            "action": <String, optional action>,
            "products": [
                {
                    "id": <String, UUID derived from stall ID>,
                    "name": <String, name of product>,
                    "categories": <String, CSV of voluntary categories>,
                    "amount": <Int, number of units>,
                    "price": <Int, cost per unit>,
                    "images": [
                        {
                            "id": <String, UUID derived from product ID>,
                            "name": <String, image name>,
                            "link": <String, URL or BASE64>
                        }
                    ],
                    "action": <String, optional action>,
                }
            ]
        }
    ]
}

As all elements are optional, an update action to a product image, may look as simple as:

{
    "stalls": [
        {
            "id": <UUID derived from merchant public-key>,
            "products": [
                {
                    "id": <String, UUID derived from stall ID>,
                    "images": [
                        {
                            "id": <String, UUID derived from product ID>,
                            "name": <String, image name>,
                            "link": <String, URL or BASE64>
                        }
                    ],
                    "action": <String, optional action>,
                },
            ]
        }
    ]
}

Checkout events

NIP-04 https://github.com/nostr-protocol/nips/blob/master/04.md, all checkout events are encrypted

The below json goes in content of NIP-04.

Step 1: customer order (event)

{
    "id": <String, UUID derived from sum of product ids + timestamp>,
    "name": <String, name of customer>,
    "description": <String, description of customer>,
    "address": <String, postal address>,
    "message": <String, special request>,
    "contact": [
        "nostr": <String, NOSTR public key>,
        "phone": <String, phone number>,
        "email": <String, email address>
    ],
    "items": [
        {
            "id": <String, product ID>,
            "quantity": <String, stall name>,
            "message": <String, special request>
        },
        {
            "id": <String, product ID>,
            "quantity": <String, stall name>,
            "message": <String, special request>
        },
        {
            "id": <String, product ID>,
            "quantity": <String, stall name>,
            "message": <String, special request>
        }

}

Merchant should verify the sum of product ids + timestamp.

Step 2: merchant request payment (event)

Sent back from the merchant for payment. Any payment option is valid that the merchant can check.

The below json goes in content of NIP-04.

payment_options/type include:

• url URL to a payment page, stripe, paypal, btcpayserver, etc
• btc onchain bitcoin address
• ln bitcoin lightning invoice
• lnurl bitcoin lnurl-pay

{
    "id": <String, UUID derived from sum of product ids + timestamp>,
    "message": <String, message to customer>,
    "payment_options": [
        {
            "type": <String, option type>,
            "link": <String, url, btc address, ln invoice, etc>
        },
        {
            "type": <String, option type>,
            "link": <String, url, btc address, ln invoice, etc>
        },
                {
            "type": <String, option type>,
            "link": <String, url, btc address, ln invoice, etc>
        }
}

Step 3: merchant verify payment/shipped (event)

Once payment has been received and processed.

The below json goes in content of NIP-04.

{
    "id": <String, UUID derived from sum of product ids + timestamp>,
    "message": <String, message to customer>,
    "paid": <Bool, true/false has received payment>,
    "shipped": <Bool, true/false has been shipped>,
}

Customer support events

Customer support is handle over whatever communication method was specified. If communicationg via nostr, NIP-04 is used https://github.com/nostr-protocol/nips/blob/master/04.md.

Additional

Standard data models can be found here here