How to get the value of the commission (fee) in the stripe payment system?

Question

Stripes

How to get the commission value in stripe payment system?

I use api to receive payments.

After payment, data comes through ipn (web hock) (example below), but they do not contain the commission that I pay for transferring money. It all looks like this:

{
  "id": "evt_1J0LaJC5KMUoB2HQfGPwW7SZ",
  "object": "event",
  "api_version": "2020-08-27",
  "created": 1623222739,
  "data": {
    "object": {
      "id": "ch_1J0LaIC5KMUoB2HQbg1J9Gz8",
      "object": "charge",
      "amount": 50,
      "amount_captured": 50,
      "amount_refunded": 0,
      "application": null,
      "application_fee": null,
      "application_fee_amount": null,
      "balance_transaction": "txn_1J0LaJC5KMUoB3HQ6LtQyyPR",
      "billing_details": {
        "address": {
          "city": "test",
          "country": "US",
          "line1": "test",
          "line2": null,
          "postal_code": "099",
          "state": "test"
        },
        "email": null,
        "name": "test test",
        "phone": null
      },

In this case, the value of application_fee and application_fee_amount is null.

How to get a commission (fee)?