Your APIs for us - Shared authorization

Shared authorization

The Shared Autorization API is a tool that gives our Clients control over the transaction authorization process. Through this API, a Client can make the authorization decision based on their own business rules, even when end users' funds are held and managed on Verestro side.

In this model, the Client's system, via a dedicated endpoint, receives an authorization request from Antaca and responds with either an approval or a decline. A positive response from the client is our signal to debit the funds from the balance in our system and finalize the payment, provided that other transactional conditions on Verestro's side are met (e.g., sufficient funds or AML rules).

A positive authorization decision from the Client doesn't guarantee the transaction will be successful, as it can still be DECLINED by Verestro for other reasons.

Features

Purpose and scope

Terminology

Security

To set secured server-server connection between our services Verestro requires a similar connection as in the case of client to Verestro communication based on the x509 certificate.
In the first step, Verestro will send to the client a CSR for the dev and production environments.
The next step is for the client to sign the CSR and send the certificate back to Verestro along with the base URL for the methods listed below. Verestro will authorize itself with each request with a certificate, which should be checked on the client side.

Idempotency Key

With some requests additional header X-Idempotency-Key could be send. This header contain unique random id allowing to identify single request.
If client send this header, operation should be triggered only once and for any further request with this key, response should be identical - in most cases, returned from cache.

example headers:

X-Idempotency-Key: 20e87975-dbfb-4c95-b239-169516c0b707

Shared Authorization API

Below you will find a list of endpoints that you should implement on your server side. Please pay special attention to the appropriate security of our connection, the syntax of requests that you can expect from the Verestro side, idempotency and the exact way in which you should respond to each request.

Transaction processing 

Remember to avoid communication errors
Verestro servers attach an X-Idempotency-Key to each request in the header. This header contains a unique ID for each request to ensure idempotence. Each request with a unique identifier in this header should be processed only once on the client side and the response to it should be identical - in most cases, returned from cache

example:

curl POST "https://server-domain.com/transactions/debit"
--header "X-Idempotency-Key: 21aa0c2a-5554-4071-bd48-b9c64a0b6270"

Transaction object

{
    "id": "b4f534ef-77c2-4f16-ab4d-496806a76fb6",
    "balanceId": "b334b384-328c-11ed-a261-0242ac120002",
    "resourceId": "9d673932-3291-11ed-a261-0242ac120002",
    "resource": "card",
    "transactionId": "ab3d89e4-3291-11ed-a261-0242ac120002",
    "referenceTransactionId": "b759931c-3291-11ed-a261-0242ac120002",
    "type": "POS",
    "amount": 10000,
    "currency": "PLN",
    "originalAmount": 10000,
    "originalCurrency": "PLN",
    "status": "AUTHORIZED",
    "description": "transaction description",
    "date": "2020-08-17T18:43:42+00:00",
    "transactionData": {
        "mcc": "5942",
        "merchantIdentifier": "003060300000005",
        "merchantName": "Book store",
        "captureMode": "NFC",
        "lastFourDigits": "4560",
        "acquirerCountry": "PL",
        "mdesDigitizedWalletId": "Google Pay",
        "cashbackPosCurrencyCode": "PLN",
        "cashbackPosAmount": 10000,
        "lastFourDpan": "7890",
        "adjustmentReasonDescription": "REFUND",
        "retrievalReferenceNumber": "749248185012",
        "cardId": "6876783"
    }
}

Integration with Shared Authorization

API Shared Authorization Details

For the process to function correctly, the Client must implement all endpoints detailed in this chapter.

Below you will find a list of endpoints that you should implement on your server side. Please pay special attention to the appropriate security of our connection, the syntax of requests that you can expect from the Verestro side, idempotency and the exact way in which you should respond to each request. If you decide to implement Shared Authorization API, remember that the implementation of all the methods below is required to ensure the API works.

Debit transaction

This kind of transaction is used to authorize transaction. 

POST https://server-domain.com/transactions/debit

headers:

Content-Type: application/json
X-Idempotency-Key: uuidV4

request body:

Description of the contents of the transaction object can be found above.

success response:

204 No Content

error responses:

422
{
    "title": "INSUFFICIENT_FUNDS",
    "detail": "some specific details provided by server"
}

422
{
    "title": "LIMITS_EXCEEDED",
    "detail": "some specific details provided by server"
}

422
{
    "title": "FRAUDS_DETECTED",
    "detail": "some specific details provided by server"
}

404
{
    "title": "BALANCE_NOT_FOUND",
    "detail": "some specific details provided by server"
}

409
{
    "title": "CLIENT_ERROR",
    "detail": "some specific details provided by server"
}

Force debit transaction

This kind of transaction is used to inform server side that transaction has occurred.
For this request, actual transaction already happen so server can not reject this request. This behavior can occur for offline transactions fe: in plane, subway, for refunds and referring to previously authorized transactions.

POST https://server-domain.com/transactions/force-debit

headers:

Content-Type: application/json
X-Idempotency-Key: uuidV4

request body:

Description of the contents of the transaction object can be found above.

response:

204 No Content

error response:

As mention in description section, we do not accept transaction rejection.

Credit transaction

Method is used to credit user balance. 

POST https://server-domain.com/transactions/credit

headers:

Content-Type: application/json
X-Idempotency-Key: uuidV4

request body:

Description of the contents of the transaction object can be found above.

success response:

204 No Content

error responses:

404
{
    "title": "BALANCE_NOT_FOUND",
    "detail": "cannot find requested balance"
}

422
{
    "title": "FRAUDS_DETECTED",
    "detail": "some specific details provided by server"
}

Force credit

Method is used to credit user balance. This kind of transaction is used to inform server side that transaction has occurred. For this request, actual transaction already happen so server can not reject this request.

POST https://server-domain.com/transactions/force-credit

headers:

Content-Type: application/json
X-Idempotency-Key: uuidV4

request body:

Description of the contents of the transaction object can be found above.

success response:

204 No Content

error response:

As mention in description section, we do not accept transaction rejection.

Reversal

Method is used to revert any changes for previous transaction. Request body will be identical to transaction witch client try to revert. If server cannot find referenced transaction then no action is required.

POST https://server-domain.com/transactions/reversal

headers:

Content-Type: application/json
X-Idempotency-Key: uuidV4

request body:

Description of the contents of the transaction object can be found above.

success response:

204 No Content

error responses:

IMPORTANT: for this method, we do not accept any error. Only satisfying behavior is to revert referenced transaction and no action if cannot find transaction.