Payment Integration for Online Shops, from Click to Booking
We connect your shop to payment providers, monitor every transaction status in real time and reconcile payments with orders automatically. Status changes flow on to ERP and accounting without manual intervention, and without data gaps.
two-way
real-time sync
50+
integration projects
< 5 s
avg. status callback
3
system layers synchronized
Fixed price · net plus VAT
- Fixed price per payment method instead of an open estimate
- Webhook, redirect and polling redundant for seamless status
- Automatic reconciliation with a daily summary report
- Downstream to ERP, inventory management and DATEV, concept included
Complete payment integration with automatic reconciliation and downstream to ERP, inventory management and DATEV at a fixed price after a free analysis. Extensions and ongoing operation on a time basis 990 € per project day (hourly rate 119 €). All prices net plus VAT. The project day is a package price for a reserved working day and therefore deliberately not a multiple of the hourly rate — the rationale is on the pricing overview.
Payments fail silently. A webhook does not arrive, a timeout goes unhandled, a chargeback lands in the system without triggering any follow-up. In manually operated shops, each of these situations means manual rework, open items or, worse, dispatched goods without confirmed payment. Our integration services close these gaps systematically: with robust webhook processing, automatic reconciliation and end-to-end status synchronization between payment provider, shop, inventory management and accounting.
What professional payment integration delivers
Payment integration covers three technical layers that together create a seamless payment flow: connecting payment methods in the shop front end, server-side transaction processing with status tracking, and forwarding all relevant events to downstream systems. Only when all three layers work cleanly together does a process emerge that requires no manual intervention and is fully traceable.
Payment Method Integration
Credit card, SEPA direct debit, prepayment, purchase on account, installment payments and other payment methods are embedded in your shop. Integration is via standardized payment APIs and tailored to your checkout flows.
Webhook Processing
Payment providers send status changes as webhooks: payment received, authorized, declined, charged back. Our integration layer receives, validates and processes these events reliably, with automatic retry for network issues.
Real-Time Status Sync
The payment status of every transaction is synchronized with the order status in the shop in real time. Incoming payment automatically triggers the fulfillment process; chargebacks lead to status changes and notifications.
Automatic Reconciliation
Daily, all transactions from the payment provider are matched against orders in the shop. Discrepancies, such as partial payments, fees or currency fluctuations, are automatically detected and reported.
Chargeback Management
Chargebacks and reversals are automatically captured in the shop, affected orders are locked and follow-up actions triggered. The process is documented and GDPR-compliant.
Downstream Bookings
Payment receipts, refunds and payment provider fees are forwarded to DATEV or your ERP, with correct account assignment and audit-proof documentation.
Reconciliation: The critical match between payment provider and shop
The reconciliation process is the core of any professional payment integration. Every day, the payment provider delivers a transaction list that must be matched against orders in the shop. In practice, these lists frequently diverge: partial refunds, transaction fees, currency conversion differences, cancelled authorizations and chargeback fees create discrepancies that are nearly impossible to trace manually. Our reconciliation logic automatically resolves these differences and only surfaces genuine discrepancies for manual review.
How the automatic matching works
Each payment provider transaction is matched against the shop using transaction ID, order number and amount. Matches are automatically marked as settled. Unmatched items go into a review list with context: transaction date, amount, payment method and available shop data. Typical discrepancies such as rounding differences of a few cents are automatically accepted under configurable tolerance rules. Only genuine differences require manual attention.
- Automatic matching across multiple key fields
- Configurable tolerance rules for minor discrepancies
- Review list only for genuinely unresolved items
- Daily summary report for accounting and controlling
Payment providers and supported platforms
Credit and Debit Cards
Integration via standardized card payment APIs with 3D Secure 2 support. Authorization, capture and chargebacks are fully controlled and logged through the integration layer.
SEPA Direct Debit
SEPA mandates are captured in the shop, validated and securely stored with the payment provider. Collections, returns (R-transactions) and mandate management run automatically through the integration layer.
Purchase on Account and Installments
Credit checks, limit management and receivable handover to payment providers are integrated into the checkout process. Payment receipts and reminders are fed back and synchronized with order status.
Open Banking and Pay-by-Bank
PSD2-compliant real-time transfers are connected via payment initiation APIs. Payment status is relayed back to the shop immediately via webhook, without manual bank statement processing.
International Payment Methods
Country-specific payment methods for markets across Europe and beyond are connected via the respective payment provider. Currency conversion and tax handling are correctly mapped in the integration layer.
Prepayment and Manual Methods
Even manual payment methods such as prepayment are integrated into the status logic. Bank statement matching, reminder processes and approval automations create a consistent process across all payment methods.
Technical workflow: From order to confirmed payment
Payment initiation at checkout
The customer selects the payment method and enters their details. The shop forwards the payment via the integration layer to the payment provider. Sensitive payment data never passes through your server but is transmitted directly between customer and provider via tokenization.
Authorization and status callback
The payment provider processes the payment and returns the result via webhook and redirect URL. The integration layer handles both channels redundantly: if the webhook arrives before the redirect, the status is already set. If the redirect comes first, the system waits for the webhook or retrieves the status via polling.
Order status update
After confirmed payment, the order status in the shop is automatically updated, the order confirmation email is triggered and the fulfillment process is released. When payment is declined, the customer is guided to select an alternative payment method without losing their order.
Downstream synchronization
The payment receipt is forwarded to inventory management and, if integrated, to DATEV or the ERP. Order positions, amounts and payment reference are passed as booking documents.
Daily reconciliation
Overnight, the integration layer reconciles the payment provider's daily transaction total against orders. Discrepancies are categorized: automatically resolvable, within tolerance or requiring manual review. The daily report goes to accounting and controlling.
Chargeback and refund processing
Chargebacks and refunds are processed as events that trigger follow-up actions in the shop. Affected orders are locked or cancelled, the payment provider is notified via the integration layer and the transaction is documented for accounting.
Not sure where your payment flows lose status?
In the free payment analysis we review checkout, webhook processing and reconciliation, and name a concrete fixed price per payment method before development starts.
Webhook resilience: When the first delivery attempt fails
Webhooks are the backbone of payment status processing, but they are inherently unreliable. Network issues, server restarts or brief outages can prevent a webhook from arriving on the first attempt. A system that only reacts to the first webhook delivery loses transaction status in these moments and creates open items.
Redundant status processing as a core principle
Integration into existing system landscapes
Payment integration is rarely an isolated interface. Typically it is part of a broader integration architecture that also connects ERP and accounting. Payment information must be forwarded to multiple downstream systems: the shipping provider, which receives the dispatch order after payment confirmation; inventory management, which reserves and releases stock; and the accounting interface, which captures every payment receipt as a booking document.
In more complex landscapes with multiple payment providers and different shop systems, a central middleware coordinates processing and routing. Each payment provider is connected as its own connector; the middleware normalizes formats and forwards events to all consumers. New payment providers can then be added without changes to the downstream systems.
Security and GDPR in payment processing
No card data on your servers
Sensitive payment data is transmitted exclusively via tokenized procedures. Your servers never see card numbers or bank data in plain text. PCI-DSS compliance is ensured through the payment provider.
Webhook authentication
All incoming webhooks are authenticated using HMAC signatures or bearer token procedures. Forged payment confirmations are detected and logged before processing.
GDPR-compliant logging
All transaction logs are stored with minimal personal data. Payment references instead of full customer data. Retention periods under commercial and tax law are automatically observed.
Common challenges and how we address them
Across our projects (project experience), the same categories of problems recur in payment integrations. The most frequent is insecure order release: shops that set the order status to 'paid' at the customer's redirect from the payment page, rather than waiting for the payment provider's final webhook. This leads to orders marked as paid when payment has not yet been finalized or was declined.
- Order release only after final payment status from the provider, not on redirect
- Idempotent webhook processing prevents duplicate status changes
- Timeout handling for stuck payments with a defined expiry process
- Partial captures for split fulfillments correctly reflected in the order system
- Currency differences on international transactions automatically detected and assigned
- SEPA mandate management with revocation process and return transaction handling
What payment integration costs
An open-ended effort estimate rarely works as the basis for a budget decision. That is why we name clear fixed prices for payment integration. The final price depends on the number of payment methods, reconciliation requirements and downstream systems, and is set bindingly after a free analysis of your payment flows, with no hidden items. On request, we bundle ongoing support with our integration and operations services.
Fixed prices for your payment integration
All prices net plus VAT. Every integration starts with a free analysis of your payment flows and a binding fixed price. Scope and system landscape determine the right path.
Single payment method
One payment method connected cleanly and status-driven.
- Connection of one payment method (card, SEPA, invoice)
- Webhook processing with retry and idempotency
- Real-time status sync with the order status
- Tokenization, no card data on your server
- Test with the provider's test transactions
Complete payment integration
Multiple payment methods with reconciliation and downstream.
- Multiple payment methods in one project
- Automatic daily reconciliation with tolerance rules
- Downstream to ERP, inventory management and DATEV
- Chargeback and refund logic
- Fixed price based on the project day after analysis
Operation & extension
Ongoing support and new payment providers.
- Add new payment providers
- Small adjustments at the 119 € hourly rate
- Middleware expansion for multiple channels
- Monitoring of payment and status flows
- Response to anomalies in status matching
Project day 990 € net as a package price, hourly rate 119 € net for smaller adjustments. Ongoing license costs from payment providers and middleware are stated transparently and separately. You receive a binding quote after the free analysis.
Scope: What this service covers and what it does not
Our payment integration covers technical connectivity, status processing and forwarding to downstream systems. Not part of this service are: legal review of your terms and conditions regarding payment methods, tax advice on payment fees, or selecting the payment provider best suited for your business. For these aspects, we recommend involving your tax advisor and legal counsel.
Choice of payment provider remains your decision
Project workflow for payment integration
- 1
Analysis of existing payment flows
We capture all payment methods you offer or plan to offer, as well as the downstream systems that need to receive payment information. This analysis produces the integration concept with data flow diagram and interface specification.
- 2
Core implementation
We implement payment method integration in the shop front end, webhook receivers and processing logic, and downstream connectors. Implementation takes place on a staging environment and is validated with the payment provider's test transactions.
- 3
Reconciliation setup
The automatic match between payment provider and shop is configured. Tolerance rules, reporting thresholds and recipients of daily reports are agreed jointly.
- 4
Go-live and parallel operation
After a successful staging test, we go live. In the first billing period, reconciliation reports are manually cross-checked to confirm the completeness of the matching. After that, the automated process takes over.
Frequently asked questions about payment integration
For deeper reading: Payment Reconciliation describes automatic matching of payments with the ERP, Tax Determination in B2B Shops explains reverse charge and tax-rate logic, and Error Handling in Interfaces shows how failed status messages stay traceable.