Capture Stripe fee from API rather than assuming rate

ontariokicker44

I ran into a headscratcher this AM as fees were not matching with what stripe was showing me. Found out that due to it being a "Instant" transfer on the client side, the fee was 2.6% rather than the normal 2.9%. This means a now have to go back and verify all of these transactions.

I am happy to work on this integration, but want to know the best course of applying it as I have made PRs in the past that are still sitting stale.

wrongecho

This is interesting, thanks for reporting. I assume they do make this accessible somewhere in the API, so it's something we should look further into.

Which stale PR are you referring to by the way?

johnny

Hey this is neat were interested but I was unsuccessful on implementing it. If you have a working way of this please share.

ontariokicker44

johnny I have been digging through the Stripe API, and they do in fact make it difficult, but it is doable.

I will see what I can cook up.

digibandit

I hope this helps at all, if not, ignore!

According to Stripe's pricing documentation, fees also vary by:

Card type (debit vs credit)
International vs domestic transactions
Processing method (online vs in-person)
Your specific Stripe agreement
Dispute and chargeback fees

From reviewing the Stripe API documentation, the actual fee information isn't directly in the charge object. You need to access the Balance Transaction:

Charge Object (Stripe Charges API):
- Contains balance_transaction field with transaction ID
Balance Transaction Object (Stripe Balance Transactions API):
- fee - actual fee in cents
- fee_details - array breaking down fee components
- net - amount after all fees

Maybe this would do it:

`// Get the charge (ITFlow probably already does this)
$charge = \Stripe\Charge::retrieve($charge_id);

// Get the balance transaction (this is the missing piece)
$balance_txn = \Stripe\BalanceTransaction::retrieve($charge->balance_transaction);

// Store actual values instead of calculated ones
$gross_amount = $charge->amount / 100;
$actual_fee = $balance_txn->fee / 100;
$net_amount = $balance_txn->net / 100;
`

The fixed percentage from settings would need to be replaced with the balance transaction API call.

According to Stripe's webhook documentation, listening for charge.succeeded events and then pulling the balance transaction data ensures you get the final, accurate fee data.

Based on Stripe's documentation on refunds and disputes:

Refunds create separate balance transactions with negative fees
Disputes generate additional balance transactions
Each needs to be tracked separately

ontariokicker44

Well I converted my cURL madness to PHP for testing.

I reckon if I change $gateway_fee = round($invoice_amount * $config_stripe_percentage_fee + $config_stripe_flat_fee, 2); to using the following code, we will get the correct fees. I will test it and make a PR for the two affected files.

$charge = $stripe->paymentIntents->retrieve($pi_id,[])["latest_charge"];

$balance_transaction = $stripe->charges->retrieve($charge, [])["balance_transaction"];

$gateway_fee = $stripe->balanceTransactions->retrieve($balance_transaction, [])["fee"]/100;

johnny

Fantastic work @ontariokicker44 this would eliminate those extra config files and make the process much simpler. Id be interested in what you encounter during your further testing.

ontariokicker44

Well the new code both works and not at the same time. When a client paid, it all worked. When I used "paid from saved card" in the UI, it 500s out with this error:

[24-Jun-2025 23:29:29] WARNING: [pool www] child 1322341 said into stderr: "NOTICE: PHP message: PHP Warning: Undefined array key "invoice_discount" in /var/www/itflow/post/user/invoice_model.php on line 7"

[24-Jun-2025 23:29:29] WARNING: [pool www] child 1322341 said into stderr: "NOTICE: PHP message: PHP Warning: Undefined array key "recurring_discount" in /var/www/itflow/post/user/invoice_model.php on line 8"

[24-Jun-2025 23:29:46] WARNING: [pool www] child 1322341 said into stderr: "NOTICE: PHP message: PHP Fatal error: Uncaught Stripe\Exception\InvalidArgumentException: The resource ID cannot be null or whitespace. in /var/www/itflow/plugins/stripe-php/lib/Service/AbstractService.php:99"

[24-Jun-2025 23:29:46] WARNING: [pool www] child 1322341 said into stderr: "Stack trace:"

[24-Jun-2025 23:29:46] WARNING: [pool www] child 1322341 said into stderr: "#0 /var/www/itflow/plugins/stripe-php/lib/Service/BalanceTransactionService.php(50): Stripe\Service\AbstractService->buildPath()"

[24-Jun-2025 23:29:46] WARNING: [pool www] child 1322341 said into stderr: "#1 /var/www/itflow/post/user/invoice.php(1065): Stripe\Service\BalanceTransactionService->retrieve()"

[24-Jun-2025 23:29:46] WARNING: [pool www] child 1322341 said into stderr: "#2 /var/www/itflow/post.php(49): require_once('...')"

[24-Jun-2025 23:29:46] WARNING: [pool www] child 1322341 said into stderr: "#3 {main}"

[24-Jun-2025 23:29:46] WARNING: [pool www] child 1322341 said into stderr: " thrown in /var/www/itflow/plugins/stripe-php/lib/Service/AbstractService.php on line 99"