Custom Sisow integration development
Appfront builds custom Sisow integrations that fully automate online payments in your webshop, platform or application. Through the Sisow REST API and webhooks, we handle iDEAL and other payment methods in your checkout, along with payment links, refunds and real-time status processing. Where you need it, transaction data flows automatically into your accounting or BI. Less manual work and a payment flow your customers can trust.
What is a Sisow integration?
Sisow is a Dutch payment service provider (PSP) for webshops and platforms. With Sisow, you offer online payment methods in your checkout, with iDEAL at the forefront, complemented by credit cards, Bancontact and other methods, plus payment links for remote payments. An integration means your own system communicates directly with Sisow's payment environment, rather than you preparing payments manually or retyping statuses.
In practice, a custom integration comes down to this: creating a transaction via the REST API as soon as a customer checks out, redirecting the customer to the payment page, receiving the payment status in real time via a webhook (notify), and writing that status back to your order or invoicing system. On top of that, we set up payment links, refunds and, where applicable, recurring payments, and we let transaction data flow automatically into your accounting or BI.
Sisow has been part of MultiSafepay since 2020, but continues to exist as a standalone connection with its own API, so existing Sisow integrations keep working as normal. Appfront builds in line with the official Sisow API documentation and the OWASP ASVS security standard, tailored to your actual checkout and order processes, so that the integration stays reliable even at peak volumes.
iDEAL and payment methods in the checkout
Offer iDEAL at the forefront, plus credit card, Bancontact and other payment methods, directly in your own checkout. Customers pay with confidence via Sisow and your order gets the correct status straight away.
Payment links for remote payments
Generate a payment link for an invoice, telephone order or reservation. Your customer pays via the Sisow payment page, and the status flows back into your system automatically, with no custom checkout required.
Refunds and status handling
Process refunds automatically from your back end and handle every payment status in real time via webhooks. Paid, failed or cancelled: your orders and accounts always stay in sync.
Our development process for Sisow integrations
We work to a proven methodology that removes uncertainty early and delivers a stable payment integration. From an initial analysis of your checkout, payment methods and order process through to go-live and ongoing management, every step is aimed at an integration your team can understand and trust.
We map out which payment methods you want to offer, how your checkout and order process work, whether payment links and refunds are needed, and which transaction data needs to flow to your accounting or BI.
We design the integration architecture, set up your merchant ID and API key securely, and define a strategy for webhook processing and error handling.
Implementation with automated tests, structured logging and monitoring. You see working builds and test payments along the way.
Controlled go-live with payment validation and safeguards, followed by ongoing management and further development.
What a Sisow integration delivers in practice
Every Sisow integration is set up specifically for your payment methods, checkout flow and related systems. Below are the features we most often deliver for organisations that use Sisow as their payment processor.
iDEAL and payment methods in checkout
The Sisow REST API connected to your webshop platform or your own checkout: iDEAL at the forefront, plus credit cards, Bancontact and other methods. Customers pay with confidence, and the payment status flows straight back into your order process.
Payment links
Generate payment links programmatically for invoices, telephone orders or reservations. Customers pay remotely via the Sisow payment page, and confirmation returns to your system automatically, which is handy for processes without a custom checkout.
Refunds from your back end
Refunds processed automatically via the API, linked directly to the original transaction. Your staff start a refund from your own system, and the status is neatly written back to the order and accounting.
Webhook status handling
Sisow sends a notify webhook whenever a payment changes status. We process this in real time, verify the status with Sisow and reliably write the result back, with retries so that no payment falls through the cracks.
Recurring payments
Where applicable, we set up recurring payments for subscriptions or periodic invoices, with an initial authorisation followed by subsequent collections. We tailor the setup to the capabilities of your Sisow agreement and your administration.
Transaction data to accounting and BI
Payments, payouts and refunds flow in a structured way into your accounting package or BI environment. Reconciliation runs automatically, so your books stay accurate and you keep clear oversight of revenue, failures and payment methods.
Typical use cases in practice
A Sisow integration works very differently from one organisation to another. We see a number of recurring patterns, and for each one we have a working setup that pays close attention to checkout, webhook status handling and the right reconciliation with your accounts.
Online shops
Dutch webshops offering iDEAL and other payment methods in their checkout via Sisow. The payment status updates the order automatically and reconciliation flows into accounting. See also our broader API integrations.
Platforms
Marketplaces and platforms that process payments between multiple parties. Transactions, payment links and payouts are driven through the Sisow API, with clear reconciliation per connected seller or supplier.
E-commerce
E-commerce businesses with multiple sales channels that want one central payment processor. Sisow connected to your webshop, point-of-sale system and accounting, so that orders and payments come together consistently in your back office.
SaaS with payments
SaaS providers charging for subscriptions and one-off purchases. First payments and, where applicable, recurring direct debits via Sisow, with status processing through webhooks and automatic registration in your accounts.
Technology we use
We build Sisow integrations using the Sisow REST API and webhooks, combined with the backend stack that suits you. The exact choice depends on your webshop platform and payment methods, so your own team can manage or further develop the implementation.
Why choose Appfront for your Sisow integration?
Appfront has extensive experience building API integrations for a wide range of organisations in the Netherlands. We always start with a thorough analysis of your existing systems and processes. An integration should not only work technically, but also add practical value to the way you work.
For every integration, we write clear documentation and make sure your own team, or any future supplier, can understand and manage it. No black box, just transparent code and clear agreements on monitoring, alerting and maintenance.
You work with a dedicated point of contact who understands both the technical and the functional side. This keeps communication short, prevents misunderstandings and speeds up decisions when choices need to be made during development.
Prefer a different PSP or a broader range of payment methods? Take a look at our MultiSafepay integration, Mollie integration and Adyen integration, as well as our wider services in API integrations, middleware, custom software and web app development.
- Experience with the Sisow REST API, webhooks and payment statuses
- Specialists in iDEAL, credit card and Bancontact at checkout
- Familiar with payment links, refunds and recurring payments
- Secure by default: API key rotation, webhook validation, scoped permissions
- Structured error handling and retry mechanisms
- Comprehensive logging and monitoring from day one
- Clear documentation your team can read and manage
- Reconciliation of transaction data for accounting and BI
- A fixed point of contact, no account managers passed around
- Ongoing maintenance and proactive further development
Security and privacy in Sisow integrations
Online payments always involve transaction and personal data, and bring card payment requirements with them. Appfront builds according to payment-specific best practices and the OWASP ASVS. This includes: merchant credentials and API keys kept in secure vaults, validation of payment status with Sisow, scoped permissions and strictly separated test and production environments. You do not store card details yourself; these go through the PSP's hosted payment pages and tokenisation, which significantly reduces your PCI DSS scope.
We document the data flows, payment methods and webhook flows so that your record of processing activities is complete and you can demonstrate compliance with the GDPR. You only store the data you need for orders and accounting; the sensitive payment processing remains with the PSP. This way you combine a smooth checkout with responsible handling of personal and payment data.
More on our security approach: information security policy and CVD policy.
- GDPR-compliant data processing and data minimisation
- No storage of card data: tokenisation via the PSP
- PCI DSS scope reduction via hosted payment pages
- Encryption in transit (TLS 1.2+) and at rest
- Role-based access and least-privilege principles
- Audit logs with traceable payment and data flows
- Automatic retries and dead-letter queues
- Monitoring and alerting for anomalous payments
Frequently asked questions about Sisow integrations
Answers to the questions we are asked most often about Sisow implementations.
A Sisow integration is a technical link between Sisow and another system, such as your webshop, platform, accounting software or own application. Through the Sisow REST API, transactions are created programmatically, payment methods such as iDEAL are offered in the checkout, and payment statuses are retrieved. Webhooks (notify) report in real time when a payment has been completed, has failed or has been cancelled. An integration can be simple (a single payment flow in the checkout) or extensive (payment links, refunds, recurring payments and transaction data passed on to your accounting or BI).
Sisow is a good fit for Dutch webshops and platforms that want to process online payments, with iDEAL at the forefront, complemented by credit cards, Bancontact and other payment methods. Since 2020, Sisow has been part of MultiSafepay, but it continues to exist as a separate connection with its own API. If you need a broader or international range of payment methods, MultiSafepay or another PSP may be a better fit, and we can look at that together with you.
A simple integration, with a single payment flow in the checkout using iDEAL and webhook status handling, is ready sooner than a more extensive project with payment links, refunds, recurring payments and a deep integration with your accounting or BI. The lead time depends on the number of payment methods, the data flows and the degree of customisation. After an intake conversation, we'll give you a realistic estimate.
We work with the Sisow REST API and webhooks (notify), combined with the backend stack that suits you, whether Node.js, Python, PHP or .NET. Authentication runs through your merchant ID and API key. For payments we set up iDEAL, credit cards and Bancontact, plus payment links and refunds where required. The integration fits your webshop platform, checkout or in-house backend.
The cost is determined by the complexity of the data flows, the number of payment methods and systems to be connected, the level of refund and recurring payment handling required, and the amount of custom work in the business logic. Ongoing management, monitoring and support also factor in. We always provide a clear quote following a no-obligation analysis of your situation. Sisow's own transaction fees are not part of our services, and you will discuss those directly with Sisow.
Yes. Online payments involve sensitive transaction and personal data. Appfront builds in line with the OWASP ASVS: API keys and merchant credentials are kept in secure vaults, webhook status is validated with Sisow, rights are scoped and environments are kept separate. You do not store card details yourself; these pass through the hosted payment pages and the PSP's tokenisation, which reduces PCI DSS scope. We document the data flows so that your record of processing activities remains complete and you can demonstrate GDPR compliance.
Yes. Appfront regularly takes over existing Sisow integrations, even when they were originally set up by another party. We review the API integration, the webhook configuration, the status handling and the error handling, document the current setup and propose improvements. From that point on, we handle adjustments, extensions and monitoring, including timely rotation of API keys.
Sisow is well suited to Dutch webshops, e-commerce businesses, platforms and SaaS providers that take online payments with iDEAL at the forefront. Typical use cases include payments at webshop checkout, payment links for invoices or remote orders, refunds initiated from the backend, and transaction data flowing automatically into your accounting or BI. For a broader international range of methods, we will look together with you at whether Sisow, MultiSafepay or another PSP fits best.
Ready to build your Sisow integration?
Tell us which payment methods you want to offer and which webshop, checkout or back end you need Sisow connected to. We're happy to help with iDEAL, payment links, refunds, webhook status handling and reconciliation with your accounts. A no-obligation first conversation will give you a clear picture of what's possible within half an hour.