Redirect Payment Guide

Documentation version 3.03, 12.08.2024

Here at Inbank we strive to help our partners sell more by simplifying purchases and making financing more accessible to customers. For exactly this reason we offer a number of sales financing solutions. Our most known credit offering is hire-purchase, also known as payment by installments.

There are several methods of how partners can integrate with Inbank, this document covers our e-POS solution. With Inbank e-POS, partners only need to add Inbank as a payment method and redirect clients to our environment, Inbank will take care of all the rest. After a successful financing process we will redirect the customer back to you.

Inbank e-POS is supplemented with Inbank Partner Portal where merchants can see detailed overview of submitted credit applications, create applications for customers and conduct contract withdrawals.

If you would like to make a partial return for a Hire Purchase or a Split into parts contract, please refer to the Partial Returns Guide.

For any questions regarding the e-POS integration process, contact Inbank at:

We will be happy to help.

Flow Overview

In general, the flow looks like this:

Inbank also sends server-to-server notification messages to ensure delivery of information about the payment session even if the customer does not return to the e-shop.

Inbank will provide you with everything you need to start using our Partner API. This includes the necessary keys, product configuration, etc. For any questions regarding the integration process, contact Inbank at:

Demo Environment

Inbank provides a separate environment for development and integration testing. The demo environment remains available during the later life cycle of our cooperation, after the integration on production environment has been launched. The demo and production environments are different, each having individual data sets.

Note that the access credentials and product codes are different in the production environment. You will be provided production specific information later on.

For testing purposes, the demo environment returns preconfigured decisions:

  • For Inbank Hire Purchase and Split into parts payment products, positive decision is given for amounts 0 - 500, 15 000 - 16 000.
  • For the Pay next month payment product, a positive decision is given for amounts 0 - 100, 150 - ...

The credit application process may include an OTP code exchange via SMS. The demo environments do not send out SMS messages. If you are testing Pay next month or Split into parts payment products, the SMS message is hardcoded to value 0000.

Guidelines for Integration Implementation

API Connectivity

Before you can initiate a session, Partner API connectivity must be configured.

Inbank will provide you an API key, used for authentication, and a unique identifier of your shop, required for building API URLs (for example POST /shops/YOUR_SHOP_UUID/pos_sessions). The keys should remain private at all times.

Authentication

The authentication process consists of the following two steps:

  1. Merchant places the API key in the Authorization header of the request.
  2. API server verifies the API key authenticity.

Authorization Header

Authorization header must have the Bearer scheme and value of your API key, for example:

Authorization: Bearer e93174d3b9158a01c861c65fab0e7f96

In case of unsuccessful authorization, the system will return the following response:

HTTP code Description
401 Unauthorized
{
    "error": [
        "unauthorized"
    ]
}

Content-Type

The HTTP header Content-Type application/json is expected in all requests, unless otherwise specified in the endpoint description. Example:

Content-Type: application/json

Payment Session State Model

For the easiest integration we have designed the session status model to be similar to other payment channels that the e-shop integrates with.



Status Description

pending

A session is created;
Credit application may be or not be in progress;
Positive but not accepted credit decisions also remain in this status until they expire.
cancelled The customer has cancelled the process.

granted

Credit has been granted to the customer, there are no obstacles from the Inbank side for sales completion.
The process is now waiting for merchant's approval, if configured so.
If the flow is configured not to wait for merchant's approval, this state may be omitted (see note below).
completed This is the target state: credit contract between customer and Inbank has been activated, merchant is liable for the delivery of goods/services.
declined Credit was declined by Inbank.
expired The session was not completed during the defined time period.

The integration flow can be configured to require a final merchant-side confirmation step, before the credit application process is completed. This is somewhat similar to the credit card flows where the amount is first reserved on the credit card account (transaction is approved), and is later 'captured' after the merchant has completed the transaction.

This may be handy if the stock is limited and the merchant does not allocate stock items before it is ensured that the customer can get the credit. If the merchant does not send the final approval (i.e. items are out of stock, order can not be completed), the granted credit is not completed.

Credit Contract State Model

Inbank will send callbacks about changes to the credit contract status. Contracts can have the following statuses:



Status Description

unsigned

A contract has been created, but has not yet been signed by the customer and/or Inbank.
signed

The contract has been signed by both the customer and Inbank.

For the flow which includes merchant approval, this state indicates that the credit has been granted by Inbank and the system is now awaiting approval from the partner to activate the contract.

activated This is the target state: credit contract between customer and Inbank has been activated, merchant is liable for the delivery of goods/services.
cancelled

The credit contract has been cancelled. This state applies only to contracts which previously were unsigned or signed.

For the flow which includes merchant approval, signed contracts get the status cancelled when the merchant has not approved the contract.

terminated An existing credit contract has been terminated. This state can only be applied to contracts which previously were activated.

Callbacks

When initiating the payment session in Inbank Partner API the e-shop should provide 3 URLs:

  • redirect URL - the URL to which the customer's browser will be redirected back after the customer has completed the credit application dialog. Regardless of the outcome of the credit application process, the customer is redirected here, even if the credit is not granted.
  • cancel URL - the URL to which the customer's browser is redirected if the customer deliberately chooses to cancel the credit application dialog.
  • callback URL - the URL to which Inbank will send server-to-server callback notifications on session status change events.

Inbank sends callbacks about the following state transition events:

  • Credit application is cancelled
  • Credit application is denied
  • Contract is cancelled
  • Contract is granted (applicable if the flow requires merchant approval of credit contracts)
  • Contract is activated (state indicating that the financing of the purchase has been completed)

If you are integrating with Inbank's Pay next month payment product, there can be cases when a customer already has an active credit contract and the new purchase is added to it. In this case, the following callbacks will be sent:

  • Purchase is rejected (credit for the purchase has been declined by Inbank, the payment session status becomes Declined)
  • Purchase is cancelled (the customer has cancelled the financing process, the payment session status becomes Cancelled)
  • Purchase is activated (financing for the purchase has been successfully provided, the payment session status becomes Completed)

Once the financing process is finalized, Inbank will send two callbacks, both with the same structure and content:

  • First one is performed on redirect_url, via the customer's browser.
  • Second one is server-to-server callback which ensures that the merchant receives the callback. It is done on callback_url.

Note that the first callback may not arrive if the customer does not press the "back to merchant" button, or if there are connectivity or technical problems at the customer's device/browser. Thus there is no guarantee that the first callback will arrive, or which one of the two callbacks will arrive first. Callback requests are lightweight triggers for initiating activities on the merchant side. They contain only minimal information.

To avoid processing accidental or malicious traffic to callback endpoints, the handlers should first verify the authenticity of the request. For more details, see the Callback authenticity validation chapter.

E-shop should process the incoming messages, at a minimum, in the following way:

  • Validate the authenticity of the request, to avoid further processing of invalid traffic.
  • Look up the pos_session identifier either from the incoming message, or from the internal database as it was persisted when the session was initiated.
  • Inspect pos_session status and process the order payment status based on the pos_session state. If needed, you can also check the purchase reference.
  • Redirect the user to the respective dialog, i.e. the "payment complete" page.

Request Structure

Both of the callbacks are sent as http POST requests, ("Content-Type" => "application/x-www-form-urlencoded"). The POST form has the following structure:

Parameter Example value Description
message %7B%22uuid%22%3A%22e4b5b81a-6d99-4a78-bd17-
46d19968eb7f%22%2C%22status%22%3A%22pending%22%2C%22
purchase_reference%22%3A%22Id+%231%22%7D
URL-encoded JSON structure containing information about the pos_session.

For more details, see the Callback message content chapter.

hmac c196e985640a6291723dc2717d264f82e70126c
34b107f3be5b22201cb147c98b9709f5184a7f2fe8268
4d6086eee07df8a46c28fc0edfdd14fd306579244664

HMAC value.

For more details, see HMAC calculation logic described in the Callback authenticity chapter.

timestamp

1549411200

Current Unix timestamp at issuing server.
See https://en.wikipedia.org/wiki/Unix_time for more details.

Callback Request Example

Request header

{"Content-Type":"application/x-www-form-urlencoded"}

Request body

message=%7B%22uuid%22%3A%223241a6d5-051b-415b-afc7-0a5aad115fcc%22%2C%22status%22%3A%22cancelled%22%2C%22
purchase_reference%22%3A%221234%22%7D&hmac=4c4686db2aac832dd2e001fdc02e2b4021dc5e49c064552215dab2ca9c564
9435562bc60e96b812ca8ea40223f500ced9c257541b43ab7fb482067c8bae7a963&timestamp=1553072069

Callback Message Content

The message contains minimal information, it is meant as a trigger to obtaining more detailed information over Partner API.

  • uuid - POS session UUID.
  • status - status of the POS session at the moment of message dispatch. For more details, see the State model chapter.
  • purchase_reference - merchant side reference, i.e. order ID. For more details, see the Session initiation chapter.

Callback Authenticity Validation

We use message authenticity hash (HMAC) transported within the POST request form field hmac. To validate the message authenticity you need to calculate the verifying HMAC based on data from the request and your secret api_key, and compare the calculated HMAC with the HMAC value passed in the request.

Verifying HMAC is calculated as SHA512 HMAC, over the timestamp and message from the request, concatenated with . delimiter. Your shop API key is used as HMAC secret.

Pseudocode for example verifying HMAC calculation:

key = your_api_key;
req_timestamp = request[timestamp];
req_message = request[message];
req_data = req_timestamp+'.'+req_message;
v_hmac = hmac("sha512", key, req_data);

JavaScript example (Postman):

key = your_api_key;
req_timestamp = decodeURIComponent(request[timestamp]);
req_message = request[message];
req_data = req_timestamp + '.' + req_message;
v_hmac = CryptoJS.HmacSHA512(req_data, key);

PHP example:

$key = $settings->api_key;
$req_timestamp = $_POST['timestamp'];
$req_message = stripslashes($_POST['message']);
$v_hmac = hash_hmac('sha512', $req_timestamp . '.' . $req_message, $key);

API Requests

This section lists the API request required for the integration with the Inbank e-POS system. The following pages contain charts with demonstration of the request sequence. The enlisted API requests are used in the following way:

  1. The shop retrieves a primary credit calculation using the POST /calculations request. The response includes an approximate monthly payment based on the credit amount and period. The final conditions will be presented in e-POS after the customer submits an application.

    Please note: Inbank payment methods should be available only for cart values that are within the price range agreed with Inbank. If you would like to receive the price range and other details of your Inbank product over API, please contact integration@inbank.ee.


  2. The e-shop initiates a payment session using the POST /pos_sessions endpoint. The request includes merchant domain name as one of the parameters. The redirect_url from the response indicates the link to which the client is redirected to complete the financing process.

  3. The e-shop redirects the client to the e-POS environment. In e-POS customers are guided through a number of dialogs to complete the financing of the purchase. After the e-POS dialogs, customers are redirected back to the e-shop. The return_url is the one the e-shop included in the POST /pos_sessions request.

  4. If the flow is configured to request merchant approval before contract activation, the e-shop waits for the callback indicating that the payment session received the status granted. At this point, the e-shop retrieves the identifier of the contract using the GET /pos_sessions request. After that, the merchant can either approve the credit contract, using POST /:contract_uuid/merchant_approval request, or cancel it, using the POST /:contract_uuid/cancel. The following step is necessary only if the contract was approved.

  5. Once the e-shop receives the callback indicating that the payment session received the status completed, the e-shop needs to check the contract status. First, the e-shop retrieves the identifier of the contract using the GET /pos_sessions request. Retrieving the contract identifier again is not required if it was previously done to approve the contract. Then the e-shop checks the status of the credit contract using the GET /contracts request. If the contract received status activated, the financing of the purchase has been successful. Note that this step should not be performed if you are integrating with the Pay next month payment product.

If you would like to make a partial return for a Hire Purchase or a Split into parts contract, please refer to the Partial Returns Guide.

API Request Flow

The chart demonstrates the sequence in which the API requests should be applied to successfully initiate the payment session, redirect the customer to e-POS and later check the credit contract status to confirm that the financing has been successful.



Please note that if you are integrating with the Pay next month payment product, you do not need to perform steps 3 and 4.

API Request Flow with Merchant Approval

The chart below applies to cases when the flow requires merchant approval prior to contract activation. The chart demonstrates the sequence in which the API requests should be applied to successfully initiate the payment session, redirect the customer to e-POS and later check the credit contract status to confirm that the financing has been successful.



Please note that if you are integrating with the Pay next month payment product, you do not need to perform step 5.

Calculator

POST /shops/:uuid/calculations

To get a credit calculation from Inbank, use the POST /shops/:uuid/calculations request.

Note that this request returns the preliminary non-personalized credit conditions. The final conditions will be presented after the customer submits a credit application and receives a positive decision.

SecuritybearerAuth
Request
path Parameters
shop_uuid
required
string
Example: a93f1f44-d5dd-4469-bfcc-c1de9e969213
Request Body schema: application/json
required
product_code
required
string

Reference to product code.

amount
required
number <double>

Total financing amount. If down payment is used, then the amount includes the down payment amount. Minimum and maximum amount depends on product setup.

period
required
integer

Number of months for repayments; allowed values depend on product setup.

payment_day
integer

Payment day.

down_payment_amount
number <double>

Down payment amount.

currency
string <double>

Currency code in uppercase. For example:

  • EUR
  • PLN
  • CZK
response_level
string
Default: "simple"

Indication of how detailed the returned response should be. It is recommended to use the minimum response level that is needed for a specific calculation, e.g. if only monthly payment is needed, then use simple.

Enum: "simple" "advanced" "payment_schedule"
Responses
201

Creates a new calculation

401

Unauthorized

403

Forbidden

404

Not Found

422

Unprocessable Entity

500

Internal Server Error

post/partner/v2/shops/{shop_uuid}/calculations
Request samples
application/json
{
  • "product_code": "product_code_here",
  • "amount": 2000,
  • "period": 12,
  • "payment_day": 5,
  • "down_payment_amount": 0,
  • "currency": "EUR",
  • "response_level": "simple"
}
Response samples
application/json
{
  • "product_code": "product_code_here",
  • "amount": 1300,
  • "period": 6,
  • "down_payment_amount": 0,
  • "payment_day": 5,
  • "response_level": "simple",
  • "currency": "EUR",
  • "payment_amount_monthly": 348.79,
  • "interest_rate_annual": 0.1,
  • "credit_cost_rate_annual": 0.1608,
  • "total_cost": 2092.74,
  • "total_cost_of_credit": 92.74,
  • "down_payment_minimum_percentage": 0,
  • "down_payment_minimum_amount": 0
}

Session Initiation

POST /shops/:uuid/pos_sessions

To start a payment session in Inbank e-POS, use the POST /shops/:uuid/pos_sessions. The response includes the identifier of the payment session - pos_session_uuid and the URL to which the customer is to be redirected - redirect_url.

* The customer_data, customer_contact_data and merchant objects and parameters included in them are optional. A request that does not contain these objects will be processed correctly. However, if the body does contain these objects, Inbank will validate the parameters passed inside them. Therefore, if the request contains customer_data, customer_contact_data, merchant objects, their parameters become required.

SecuritybearerAuth
Request
path Parameters
shop_uuid
required
string
Example: a93f1f44-d5dd-4469-bfcc-c1de9e969213
Request Body schema: application/json
required
object
object

Data used to pre-fill credit application fields regarding the customer.

object

Data used to pre-fill credit application fields regarding customer contact information.

object

Data used to pre-fill credit application fields regarding customer address.

object

Credit application related attributes that a merchant can pass, and Inbank can use to pre-fill applications in e-POS.

user_ip
string

Customer browser IP address as seen by e-shop.

object

Information about the technical environment of the partner side integration, e.g. "ecom_platform":"string", "module":"string"

additional_data
object

Container for additional data that e-shops can pass to e-POS dialogs (pre-filling forms).
Any keys are allowed.

required
object
object
object
Responses
201

Creates a new POS session

401

Unauthorized

403

Forbidden

404

Not Found

422

Unprocessable Entity

500

Internal Server Error

post/partner/v2/shops/{shop_uuid}/pos_sessions
Request samples
application/json
{}
Response samples
application/json
{}

Session Details

GET /shops/:shop_uuid/pos_sessions/:pos_session_uuid

When a user is redirected back to e-shop, or when a callback notification is received, the e-shop should make a GET /shops/:shop_uuid/pos_sessions/:pos_session_uuid request to inspect session details. The response contains the credit_contract_uuid value which is used in the GET /contracts request to check the status of the contract. If the flow is configured to request merchant approval before credit contract activation, this value is also used in the POST /:contract_uuid/merchant_approval or the POST /:contract_uuid/cancel request, to either approve or cancel the credit contract.

It is important to inspect the value of the status. If the status is completed, then from the e-shop order perspective it has been paid, and the goods can be shipped.

SecuritybearerAuth
Request
path Parameters
shop_uuid
required
string
Example: a93f1f44-d5dd-4469-bfcc-c1de9e969213
pos_session_uuid
required
string
Example: 5e3a459a-aada-4d81-b6ad-09cb9483c8bf
Responses
200

Return POS session details

401

Unauthorized

403

Forbidden

404

Not Found

500

Internal Server Error

get/partner/v2/shops/{shop_uuid}/pos_sessions/{pos_session_uuid}
Request samples
Response samples
application/json
{
  • "uuid": "5e3a459a-aada-4d81-b6ad-09cb9483c8bf",
  • "product_code": "loan",
  • "total_amount": 9000,
  • "currency": "EUR",
  • "status": "pending",
  • "salesperson_reference": "Earl James",
  • "locale": "et-ET",
  • "user_ip": "192.128.00.01",
  • "customer_data": {
    },
  • "customer_contact_data": {
    },
  • "customer_address_data": {
    },
  • "credit_application_data": {
    },
  • "integration_info": {
    },
  • "additional_data": {
    },
  • "purchase": {
    },
  • "created_at": "2020-03-04T12:46:06+01:00",
  • "valid_until": "2020-03-11T12:46:06+01:00",
  • "credit_application_uuid": "471e6282-3384-412b-af7b-646eb8f04391",
  • "credit_contract_uuid": "788ec8c4-c497-470b-8505-2303f151d427"
}

Contract Approval

POST /partner/v2/shops/:shop_uuid/contracts/:contract_uuid/merchant_approval

If the flow is configured to request merchant approval, the e-shop will receive the callback informing that the payment session has received status granted. This means that the credit has been approved by Inbank.

To approve the contract, the e-shop first needs to perform the GET /pos_sessions request, which, among other parameters, returns the credit_contract_uuid. This identifier can then be used to approve the credit contract.

The request does not require any parameters to be passed in its body.

SecuritybearerAuth
Request
path Parameters
shop_uuid
required
string
Example: a93f1f44-d5dd-4469-bfcc-c1de9e969213
contract_uuid
required
string
Example: 788ec8c4-c497-470b-8505-2303f151d427
Responses
204

Merchant approval and activation

401

Unauthorized

403

Forbidden

404

Not Found

422

Unprocessable Entity

500

Internal Server Error

post/partner/v2/shops/{shop_uuid}/contracts/{contract_uuid}/merchant_approval
Request samples
Response samples
application/json
{
  • "message": "unauthorized"
}

Contract Cancellation

POST /partner/v2/shops/:shop_uuid/contracts/:contract_uuid/cancel

If the flow is configured to request merchant approval, the e-shop will receive the callback informing that the payment session has received status granted. This means that the credit has been approved by Inbank.

To cancel the contract, the e-shop first needs to perform the GET /pos_sessions request, which, among other parameters, returns the credit_contract_uuid. This identifier can then be used to cancel the credit contract.

The request does not require any parameters to be passed in its body.

SecuritybearerAuth
Request
path Parameters
shop_uuid
required
string
Example: a93f1f44-d5dd-4469-bfcc-c1de9e969213
contract_uuid
required
string
Example: 788ec8c4-c497-470b-8505-2303f151d427
Responses
204

Cancel contract

401

Unauthorized

403

Forbidden

404

Not Found

422

Unprocessable Entity

500

Internal Server Error

post/partner/v2/shops/{shop_uuid}/contracts/{contract_uuid}/cancel
Request samples
Response samples
application/json
{
  • "message": "unauthorized"
}

Contract Details

Note that this request should not be used if you are integrating with the Pay next month payment product.

GET /partner/v2/shops/:shop_uuid/contracts/:contract_uuid

Once the credit contract UUID has been retrieved via the GET /pos_sessions request, the e-shop can check the status of the credit contract using the GET /partner/v2/shops/:shop_uuid/contracts/:contract_uuid request. The response will include the status parameter. If the status is activated, the purchase has been successfully financed by Inbank and the purchase items can be forwarded to the customer.

SecuritybearerAuth
Request
path Parameters
shop_uuid
required
string
Example: a93f1f44-d5dd-4469-bfcc-c1de9e969213
contract_uuid
required
string
Example: 788ec8c4-c497-470b-8505-2303f151d427
Responses
200

Returns contract details

401

Unauthorized

403

Forbidden

404

Not Found

500

Internal Server Error

get/partner/v2/shops/{shop_uuid}/contracts/{contract_uuid}
Request samples
Response samples
application/json
{
  • "contract": {
    }
}