Retrieve "Shopify Payments" fees by Order # for reconciliation with Accounting + Bank Deposits?

OK so this isn't a total solution but I am updating as I go and will continue to edit this answer until I find a full solution (or until someone who has one adds an answer).

Whitelist / API Endpoint Approval Required

I found a Shopify API endpoint that should give the information I am looking for over here: https://help.shopify.com/en/api/reference/shopify_payments/transaction

According to the Shopify API docs the response should contain the Fee Amount and the API Endpoint would be: /admin/shopify_payments/balance/transactions.json

That would get me exactly what I need, except that sending a properly formatted request to the avoid Endpoint gives the following response:

{
    "errors": "[API] This action requires merchant approval for read_shopify_payments_payouts scope."
}

Basically it seems like it needs to be approved per merchant making it a less than ideal solution for you guys as an App. I requested the functionality and will add to this if it makes something easier (when / if it's granted to our account).

Public Access to Similar Fee Data

While playing around with some of the other endpoints I ran into this one (which IS public and accessible for Apps — I am a partner / develop Shopify Apps myself) which seems to provide similar functionality:

https://help.shopify.com/en/api/reference/orders/transaction

When making a call (and receiving the "kind": "sale" result for a given Order Id) I get the following pieces of JSON that are interesting:

        "gateway": "shopify_payments",
        "status": "success",

and more importantly:

"balance_transaction": {
                    "id": "XXXXXXXXXX",
                    "object": "balance_transaction",
                    "amount": 12881,
                    "available_on": 1553040000,
                    "created": 1552943224,
                    "currency": "usd",
                    "description": "[email protected]",
                    "exchange_rate": null,
                    "fee": 339,
                    "fee_details": [
                        {
                            "amount": 339,
                            "application": "ca_1vQrdCwnvOuC2Ypn5R9whwXkGxb4XJjx",
                            "currency": "usd",
                            "description": "Shopify Payments application fee",
                            "type": "application_fee"
                        }
                    ],

Where the JSON 'amount; property corresponds to the invoice sales amount (including shipping) as a decimal free value.

The "fee": 339 appears to indicate the fee amount deducted by Shopify Payments (based on the JSON idicator attached: description": "Shopify Payments application fee").

Yep. That's the Fee.

After checking the Shopify Account tier (in this case Advanced) the fees deducted should be: 2.4% + 30¢ meaning that the total does match — 2.4% * $128.81 = $3.09144 + 30 cents (per transaction) = $3.39.

So basically everything exists (with no whitelisting required) to get the fee amounts on a per order basis for Shopify Payments users. This probably includes the Shopify Fees charged to external gateways as well although I don't use one so I can't say for sure.

That endpoint functionality means Shopify Fees likely COULD be added to any Shopify App that integrates with an accounting system — but also means it is relatively easy to pull in after the fact if the integration you are working with deposits the Invoiced amount into accounting but DOES NOT add a negative line item associated with the Shopify Fees — like mine does.

Still leaves me with some questions but at least the initial 'How do I find the Shopify Fees?' question is taken care of.