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Integrating a payment service provider

To integrate a PSP (payment service provider), develop an adapter that implements the NewStore Payment provider webhooks.

An adapter serves as an intermediary between NewStore Omnichannel Cloud and a specific PSP to enable the communication of transaction information.

Develop an adapter for each provider and tell NewStore about the payment providers you want to integrate with. NewStore supports integrations with all payment providers.

How payments work

In NewStore Omnichannel Cloud, the following entities are involved in a payment transaction:

Payment accounts

The payment account entity can be used to track balance and payments for an entity of the platform. To do this, assign the payment account the same ID as the ID of the entity you want to track. For example, if you want to a payment account to track a sales order, create a payment account object with the ID of the sales order.

The balance is modified when an order is modified (amendment/cancelation) and the payment amount is captured, refunded or revoked.

Financial instruments

A financial instrument represents a set of transactions that track changes in the available-for-capture (capturable) amount and available-for-refund (refundable) amount. A financial instrument is associated with a payment account and uniquely identified in NewStore Omnichannel Cloud.

A financial instrument can be used to:

  • Capture: Transfer an amount from the customer to your business. This decreases the available-for-capture amount for the specific instrument and optionally increases the available-for-refund transaction. A financial instrument supports multiple capture operations until available-for-capture amount is 0. If a capture operation results in an increase in the available-for-refund amount, the convention is to return two different transactions.
  • Refund: Transfer an amount from your business to the customer. This decreases the available-for-refund amount for the specific instrument. A financial instrument supports multiple refund operations until available-for-refund is 0.
  • Revoke: Transfer withheld funds to the customer and set the available-for-capture amount to 0.

Developing the adapter

To develop the adapter, implement the Payment provider webhooks to execute the operations requested by NewStore Omnichannel Cloud. The main task consists of tracking the transactions in a financial instrument and ensuring that the capturable and refundable amounts are updated.

The following sequence diagram represents a typical workflow:

sequenceDiagram participant N as NewStore participant A as Adapter participant P as PSP Note left of N: A payment is initiated. The payment can be pre-captured, pre-authorized or tokenized. N->>A: /financial_instruments (POST) activate N A->>P: Create instrument A->>N: financial instrument deactivate N Note over N,A: The instrument is ready to have transactions applied to it. Note left of N: An order is fulfilled. Capture the amount. N->>A: /financial_instruments/{id}/_capture activate N A->>P: Capture the amount A->>N: Transactions deactivate N Note left of N: An order is canceled. Revoke the amounts. N->>A: /financial_instruments/{id}/_revoke activate N alt Type='captured' A->>P: Refund the amount else Type!='captured' A->>P: Revoke the amount end A->>N: Transactions deactivate N Note left of N: An item is returned. Refund the amount. N->>A: /financial_instruments/{id}/_refund activate N A->>P: Refund the amount A->>N: Transactions deactivate N

Pay attention to the idempotency keys of the requests. Ensure that you send the same response every time you receive a request with a given idempotency key.

For example, if you receive 3 requests containing the idempotency key abcd, whether the body has changed or not, give the same response to these 3 requests.

Workflow examples

Depending on the instrument and the state of the order, process the NewStore request differently.

The following examples represent some standard business cases that trigger a number of operations on the instrument all of which modify the 2 main characteristics of an instrument: the capturable and refundable amounts.

Authorized or tokenized instrument

Return scenario

Two items ($50 each) are shipped from 2 different location and are then returned.

Here is an example of possible requests:

Authorize requestCapture requestCapture requestRefund requestRefund request
ContextCustomer places an order.One item is fulfilled.The other item is fulfilled.One item is returned.The other item is returned.
Capture amount100-50-5000
Refund amount05050-50-50
Partial cancellation scenario

An order contains 2 items ($50 each):

  1. One item is shipped.
  2. The customer cancels the order (the remaining item that hasn't been shipped).
  3. The customer returns the received item.

Here is an example of possible requests:

Authorize requestCapture requestRevoke requestRefund request
ContextCustomer places an order.One item is fulfilled.The order is partially canceled.The fulfilled item is returned.
Capture amount100-50-500
Refund amount0500-50

Pre-captured instrument

For pre-captured instruments, there is no revoke since the instrument has already been captured. In this case, NewStore Omnichannel Cloud requests a revoke, but a refund operation should be performed by the payment service provider.

Order cancellation scenario 1

The order is canceled before its fulfillment.

Here is an example of possible requests:

Authorize requestRevoke/Refund request
ContextCustomer places an order.Customer cancels the order.
Capture amount100-100
Refund amount00
Order cancellation scenario 2

The order is canceled after its fulfillment.

The order contained 2 items ($50 each):

  1. The amount $100 was authorized and $50 was captured.
  2. The customer cancels the order (Subtract the captured amount $50 from the authorized amount $100 to calculate the refundable amount $50).
  3. The cancellation makes the remaining authorized amount $50 void.

Here is an example of possible requests:

Authorize requestCapture requestRevoke requestRefund request
ContextCustomer places an order.The order is fulfilled.Customer cancels the order.The fulfilled item is returned.
Capture amount100-50-500
Refund amount0500-50


Before you start the integration, ensure your infrastructure offers the following:

  • A web URL (HTTPs) where the requests from NewStore Omnichannel Cloud can be posted.
  • An API key provided by your system to access the above URL. Insert it in the authorization header of your requests.

Creating the financial instruments

Creating the financial instrument is the first step before creating transactions.

NewStore defines the instrument to create depending on the customer's payment method and PSP. For example, NewStore can get a token from Stripe that represents the card to be charged; or NewStore can receive a gift card number from the customer during checkout.

Based on this definition of the instrument, NewStore Omnichannel Cloud calls the Create financial instrument method in order to have the adapter (your implementation) create a financial instrument that can be used to apply financial transactions as the order goes on through its life cycle .

When receiving an instrument creation request, pay attention to:

  • The metadata property.

    It is owned by NewStore but as an integrator, you decide what it contains and that you need for your implementation. A typical example is the Stripe token that was acquired when the payment was initiated. Get in touch with your contact point at NewStore to edit its content.

  • The instrument.type property.

    It represents the type or state the instrument, so it also indicates whether the instrument already exists at the time of the request. This means that depending on this property, you apply a different workflow.

    It can be one of the following values:

    Instrument typeDescriptionTypical implementation
    tokenThe instrument exists but is not authorized.Authorize the instrument and return a list of transactions.
    authorizedThe instrument is already authorized. The identifier is a reference to the authorization. For example, a Stripe charge.Validate the instrument's data.
    capturedThe instrument is already captured. For example, a PayPal transaction.Validate the instrument's data to ensure that the total amounts of capture/refund request is in the limits of the instrument.

The response to the Create financial instrument method contains the transactions on the instrument that set the capturable and refundable amount.

In the response, notice:

  • The transaction_id property. As an integrator, you own this property. We strongly recommend that you assign a PSP-generated reference to this field instead of generating you own ID. This facilitates log analyses as this property directly corresponds to the PSP-owned transaction.

  • The metadata property. You can use this field to send information to NewStore that will not be manipulated by the system but that you can retrieve in different parts of NewStore Omnichannel Cloud, for example you can output this data in the templates sent to customers.

    Refer to the Create financial instrument method documentation for the response schema.

Capture or refund

These operations modify the capturable and refundable amounts of the instrument.

  • Capture happens at the end of the order workflow, once the items have been fulfilled. See Getting started with the NewStore platform for more information about the payment workflow.
  • Refund happens when a customer returns an item.

Once the financial instrument has been created, NewStore requests financial operations on it using the Capture webhook and the Refund webhook. Both methods have the same payloads. The response to a capture/refund call is a list of transactions that modify the capture/refund amount(s).


Even for pre-captured instruments (type = captured), return a transaction confirming the change in the capture_amount available.

If the request fails, NewStore retries the request till around 45 days from the time of the first call. A manual retry call does not interrupt the automated platform retries.


Revoke happens when a customer cancels a complete or partial order. A partial order is when an item has been shipped and the cancelation request is received, which cancels only the items that still have not been fulfilled.

This operations releases all withheld funds from the instrument. To request a revoke, NewStore calls the Revoke webhook. The request is similar to the capture/refund method without the arguments property. The response is a transaction that sets the balance to 0. If the instrument type is captured, you cannot ask your PSP to revoke the instrument. You have to request a refund instead.


The instrument type changes how you respond to the revoke request. If the type is captured, you cannot revoke it and treat the revoke request as a refund request .

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