Paddle Billing transactions which include credit

With Paddle Billing, credits maybe added to a transaction such as if a subscription's plan is upgraded, a credit is added for pro-rated updates.

For example, here's a webhook event for a plan upgrade from $15 to $20

{
  "event_id": "evt_abc123",
  "event_type": "transaction.completed",
  "occurred_at": "2023-10-18T10:56:33.696554Z",
  "notification_id": "ntf_abc123",
  "data": {
    "id": "txn_abc123",
    "items": [
      {
        "price": {
          "id": "pri_abc123",
          "status": "active",
          "quantity": {
            "maximum": 100,
            "minimum": 1
          },
          "tax_mode": "account_setting",
          "product_id": "pro_abc123",
          "unit_price": {
            "amount": "2000",
            "currency_code": "USD"
          },
          "custom_data": null,
          "description": "20 monthly",
          "trial_period": null,
          "billing_cycle": {
            "interval": "month",
            "frequency": 1
          },
          "unit_price_overrides": []
        },
        "price_id": "pri_abc123",
        "quantity": 1,
        "proration": {
          "rate": "0.99966",
          "billing_period": {
            "ends_at": "2023-11-18T10:41:13.871061Z",
            "starts_at": "2023-10-18T10:56:23.015Z"
          }
        }
      }
    ],
    "origin": "subscription_update",
    "status": "completed",
    "details": {
      "totals": {
        "fee": "150",
        "tax": "333",
        "total": "1999",
        "credit": "1500",
        "balance": "0",
        "discount": "0",
        "earnings": "1516",
        "subtotal": "1666",
        "grand_total": "499",
        "currency_code": "USD"
      },
      "line_items": [
        {
          "id": "txnitm_abc123",
          "totals": {
            "tax": "333",
            "total": "1999",
            "discount": "0",
            "subtotal": "1666"
          },
          "product": {
            "id": "pro_abc123",
            "name": "My Test Payments App",
            "status": "active",
            "image_url": null,
            "custom_data": null,
            "description": null,
            "tax_category": "standard"
          },
          "price_id": "pri_abc123",
          "quantity": 1,
          "tax_rate": "0.2",
          "proration": {
            "rate": "0.99966",
            "billing_period": {
              "ends_at": "2023-11-18T10:41:13.871061Z",
              "starts_at": "2023-10-18T10:56:23.015Z"
            }
          },
          "unit_totals": {
            "tax": "333",
            "total": "1999",
            "discount": "0",
            "subtotal": "1666"
          }
        }
      ],
      "payout_totals": {
        "fee": "150",
        "tax": "333",
        "total": "1999",
        "credit": "1500",
        "balance": "0",
        "discount": "0",
        "earnings": "1516",
        "fee_rate": "0.05",
        "subtotal": "1666",
        "grand_total": "499",
        "currency_code": "USD",
        "exchange_rate": "1"
      },
      "tax_rates_used": [
        {
          "totals": {
            "tax": "333",
            "total": "1999",
            "discount": "0",
            "subtotal": "1666"
          },
          "tax_rate": "0.2"
        }
      ],
      "adjusted_totals": {
        "fee": "150",
        "tax": "333",
        "total": "1999",
        "earnings": "1516",
        "subtotal": "1666",
        "grand_total": "499",
        "currency_code": "USD"
      }
    },
    "checkout": {
      "url": "https://localhost:3000/charges?_ptxn=txn_abc123"
    },
    "payments": [
      {
        "amount": "499",
        "status": "captured",
        "created_at": "2023-10-18T10:56:23.651391Z",
        "error_code": null,
        "captured_at": "2023-10-18T10:56:26.068085Z",
        "method_details": {
          "card": {
            "type": "visa",
            "last4": "4242",
            "expiry_year": 2030,
            "expiry_month": 1
          },
          "type": "card"
        },
        "payment_attempt_id": "769c7528-df6b-4ca5-91b6-41d1ee38094d",
        "stored_payment_method_id": "de146e8c-6361-433f-8d15-5b2ee59efd9b"
      }
    ],
    "billed_at": "2023-10-18T10:56:23.434705Z",
    "address_id": "add_abc123",
    "created_at": "2023-10-18T10:56:23.50414Z",
    "invoice_id": "inv_abc123",
    "updated_at": "2023-10-18T10:56:33.115863546Z",
    "business_id": null,
    "custom_data": null,
    "customer_id": "ctm_abc123",
    "discount_id": null,
    "currency_code": "USD",
    "billing_period": {
      "ends_at": "2023-11-18T10:41:13.871061Z",
      "starts_at": "2023-10-18T10:41:13.871061Z"
    },
    "invoice_number": "3731-10089",
    "billing_details": null,
    "collection_mode": "automatic",
    "subscription_id": "sub_abc123"
  }
}

You can see there's a credit value in details.totals. Should the Paddle Charge code be updated so it creates charges for the payments amount? Or should it create the credits as refunds? I'm unsure if Stripe does the same or supports credits.

pay-rails / pay

Paddle Billing transactions which include credit #874