MplusKASSA
In this section we will explain the steps needed to connect your MplusKASSA POS to a card terminal and/or QR
Information
Summary | |
|---|---|
Available payment methods | Online payment methods (QR) + instore (including card refunds) |
Name | |
Download location | No installation required, based on webhooks |
Refunds | QR payments can be refunded via My.pay |
Requirements | Webhooks module |
Set-up
Installation & configuration
We have developed so called middleware to connect your Pay. account to MplusKASSA. This way, you do not have to install any external software.
There are 3 steps to this integration:
Step 1: connect the accountsSend an email to [email protected] with the following information:
Subject: MplusKASSA
AT-code: [AT-code of the Pay. account you would like to connect]
SL-code: [sales location in Pay. where the monies should go]
TH-code: [ID of your card terminal optional]
Secret token: [secret token of your MplusKASSA]
Branch number: [Branch (filiaal) number in the MplusKASSA that will be starting the transaction]
Workstation number: [Workstation (werkplek) number of the MplusKASSA that will be starting the transaction]
Do not continue to step 2, until you have received a subscription ID from Pay.
Where do I find this information?
The first 3 you will find in My.pay under Settings > Sales location. The TH-code you will find under Settings > Card terminals.
The other 3 you will find in your POS.
For the secret token go to Beheer > Instellingen > Webhooks

The branch and workstation number can be found in multiple places, like:
Main menu at the top

In the till system, top right

Go to Beheer > Instellingen > Webhooks and enter the following:
- Subscription ID: enter the subscription ID exactly as received from Pay.
- Endpoint: https://connector-q.pay.nl/mpluskassa/webhooks
Example
Your settings should now look like this:
Subscription ID: as received from Pay.
Secret token: the same token you shared with Pay. in step 1
Endpoint: entered as per step 2

The buttons can be added to the checkout screen or as shortcuts. In this example, we will add them as buttons on the checkout screen.
- Go to Beheer > Financieel > Betaalwijzen
- Add payment method:
- For PIN > payment method ID: K_PAY_PIN
Description: PAY. PIN - For QR > payment method ID: K_PAY_QR
Description: PAY. QR
To use the QR option, the letters QR have to be included in the payment method ID as our application filters on this ID whether to start an instore transaction or a QR transaction
- For PIN > payment method ID: K_PAY_PIN
- Activate the payment method for the relevant tills by ticking the right boxes
- Activate the following webhook events specifically for Pay:
a. cancelExternalPayment (betaalwijze: PAY. PIN en/of PAY. QR)
b. pollExternalPayment (blocking/polling. Betaalwijze: PAY. PIN en/of PAY. QR)
c. requestCancelExternalPayment (blocking. Betaalwijze: PAY. PIN en/of PAY. QR)
d. startExternalPayment (blocking. Betaalwijze: PAY. PIN en/of PAY. QR) - The following settings are general settings, but our application does use them in the payment flow:
e. cancelPayment (blocking)
f. completeSession (blocking)
g. startPayment (blocking)
h. startSession (blocking)
More information

Check the tills

Webhooks

You have now successfully connected your Pay. account to MplusKASSA
Releases
Please note that this is regarding middleware. These releases are deployed on our servers and no action is required on your side. This is purely for your information.
Release | Version | Description |
|---|---|---|
27.01.2026 | 0.1.30 | Small under-the-hood fixes |
02.08.2023 | 0.1.29 | Aanmaken van retourbon is nu mogelijk |
20.06.2023 | 0.1.28 | articleNumber wordt unknown wanneer deze niet bekend is Price wordt 0 wanneer deze niet bekend is VATpercentage wordt 0 wanneer deze niet bekend is |
07.06.2023 | 0.1.27 | Productnamen langer dan 255 karakters worden nu afgekapt in de applicatie, zodat er geen error wordt teruggegeven |
Features
Instore and card refunds
- Add products to the order and/or table
- Go to Pay (Afrekenen)
- On the checkout screen, select the PAY. PIN button you added earlier
- In the bottom right corner, select Pay (Afrekenen)
- The amount due will now be shown on the terminal and the customer can complete their purchase
To process a card refund, you follow the same steps. There will just be a negative amount to start the transaction.
Please do ensure card refunds are activated on the terminal.
QR
It is possible to show a QR code on a customer display. The code can be scanned by a phone camera or directly via an app (like in3, WeChat or Alipay).
- Add products to the order and/or table
- Go to Pay (Afrekenen)
- On the checkout screen, select the PAY. QR button you added earlier
- In the bottom right corner, select Pay (Afrekenen)
- The customer display should now show a QR code
- The customer can scan this code with a device with a camera and internet connection (like a phone)
- The hosted payment page will open on their device, which will show all activated payment methods of the sales location
Troubleshooting
Error | Possible solution |
|---|---|
Deze webhook heeft geen goede reactie gegeven. Bekijk eventueel het logboek voor meer details |
|
Terminal in use for max. [xx] seconds | Check whether the webhook event startExternalPayment is only enabled to receive data. The column Polling should be disabled. |
Updated 4 days ago