# Get the Trustap fee for an online transaction

This returns the Trustap fee, in the currency's smallest unit,
for a transaction involving goods with the supplied price. See
[the Stripe
documentation](https://stripe.com/docs/currencies#zero-decimal)
for more details.

Endpoint: GET /transactions/{transaction_id}/charge
Version: 0.1.0
Security: OAuth2, APIKey

## Path parameters:

  - `transaction_id` (integer, required)

## Query parameters:

  - `price` (integer, required)
    The price of the goods being sold in this transaction, in
the currency's smallest unit. For example, if a trading
card is being sold for $12.34 (with currency as usd),
then the request for the charge for this transaction would
be /charge?price=1234&currency=usd.

  - `quantity` (integer)
    When creating transactions from a multi-use listing, the
quantity parameter can be provided in order to generate a
charge for the given price multiplied by the given quantity.
See /multi_use_listings/{listingId}/create_transaction
for more details.

  - `payment_method` (string)
    The payment method that will be used to pay for the
transaction. This is necessary because different payment
methods may result in different fees.

The default value is card.

  - `charge_config` (integer)
    The charge config for which the charge amount is computed.

## Response 200 fields (application/json):

  - `charge` (integer, required)
    The Trustap fee that the buyer will pay, in the currency's
smallest unit, for a queried amount. See [the Stripe
documentation](https://stripe.com/docs/currencies#zero-decimal)
for more details.
    Example: 340

  - `charge_calculator_version` (integer, required)
    The version of the Trustap charge calculator that was used
to calculate this charge.

This property is present for error-handling purposes. The
Trustap API allows apps and users to query how much Trustap
will charge for a transaction before creating a transaction.
Trustap then requires the queried charge to be provided when
creating a transaction or listing. At this point the charge
is calculated again and checked against the provided charge,
to ensure that the charge calculated for the new resource is
the same as the one shown to the user. In the unlikely event
that the Trustap charge calculator used to calculate the
charge has been updated, then the
charge_calculator_version property will be used to return
an incorrect_calc_version to the API client, which will
indicate that the /charge endpoint should be queried again
to get the newest charge value.
    Example: 5

  - `charge_config` (integer)
    The config for which the charge amount is computed.
    Example: 1

  - `charge_postage_buyer` (integer)
    When the transaction handles the generation of postage
labels, then charge_postage_buyer will be added to cover this
fee together with charge_postage_client
    Example: 1000

  - `charge_postage_client` (integer)

  - `charge_seller` (integer, required)
    The Trustap fee that the seller will pay, in the
currency's smallest unit, for a queried amount. See [the
Stripe
documentation](https://stripe.com/docs/currencies#zero-decimal)
for more details.

  - `currency` (string, required)
    Example: "eur"

  - `payment_method` (string)
    Example: "card"

  - `price` (integer, required)
    Example: 10000

## Response 400 fields (application/json):

  - `code` (string, required)
    Example: "negative_price"

  - `error` (string, required)
    A contextual description of the error that occurred. When
handling errors the code field should be used to determine
the type of error that occurred, as the text in the error
field may change unexpectedly.
    Example: "`price` cannot be negative"