Custom Online and Mobile Payment Platform

Do you need your own payment platform?

A ready-made payment service is suitable when you sell through a standard online store and only need card payments, cash on delivery or bank transfers. A custom solution makes sense when payment is part of a more complex process: you distribute funds to different parties, work with subscriptions, have wallets, need your own dashboard or connect several banks and payment providers.

The platform can serve merchants, end customers, operators, accountants and administrators with different permissions. For regulated financial activities, the software does not replace the licensed payment operator or other responsible institution. We define the roles and their boundaries from the outset, so technical and regulatory responsibilities do not become mixed.

How is a card payment processed, including Mastercard?

When a payment is made, the platform creates an order and sends the required data to the selected payment provider. Card details can be entered on a secure page or field hosted by the provider, so your system does not store the card number. The provider then sends the request through the authorization chain, which includes the card scheme, such as Mastercard, the issuing bank and the acquiring bank.

Your system receives the result: an approved, declined, pending, cancelled or refunded payment. We do not rely solely on the customer being redirected back to the website. We also process server-side notifications from the payment provider, verify the signature or other authentication mechanism, and record the change in the transaction history. This prevents an order from being marked as paid simply because someone opened a successful URL in a browser.

What are the roles of the payment operator and integrations?

The payment operator or provider handles the connection to card schemes, banks and authorization mechanisms and, depending on the model, may also manage card token storage, refunds and settlement. The issuing bank decides whether to approve the transaction. The acquiring bank accepts the transaction from the merchant. Your platform coordinates the business logic around these events and shows what happened.

We connect the system to the APIs of banks, payment institutions, card operators and other providers. The integration may include payment creation, a 3-D Secure flow, tokenized recurring payments, subscriptions, partial or full refunds, status checks, payouts to recipients and automatic matching with an invoice or order. When needed, we also connect payments to an ERP, CRM, online store or mobile app through API integrations.

What do you get in the platform?

We design the functionality around the way you move money and documents. The system usually includes:

• Profiles for customers, merchants, operators and administrators, with separate roles and permissions.
• Orders, payments, refunds, fees, commissions and linked invoices.
• Transaction history with an ID from your system and an ID from the payment provider.
• A dashboard for current and failed operations, pending notifications and cases requiring review.
• Automatic matching of bank statements, payments and accounting documents when the provider supplies the required data.
• Exports and reports by period, merchant, payment method, status and currency.
• Notifications by email, SMS or mobile app when a payment succeeds, is declined or refunded, or when action is required.

How do you support mobile payments?

The mobile app does not need to replicate the entire payment logic. It sends a request to the server, which creates the transaction, and the result is returned to the app through a secure API flow. This keeps the rules for amounts, access, statuses and refunds in one place for iOS, Android and the web.

We can add in-app payments, mobile notifications, transaction history, QR code scanning, a saved payment method using the provider's token and biometric confirmation when supported by the selected integration. If needed, we can combine the platform with mobile app development.

How do you ensure security and traceability?

We separate the public-facing area, administration panel and server services. We use encrypted connections, access control, rate limiting, action logs and separate development and production environments. Card data is routed to the appropriate payment provider instead of being stored in the system unnecessarily.

Every operation has a history: who created it, what its status was, which notification was received and what action followed. This helps with customer disputes, resending a notification, technical failures or accounting checks. The specific requirements for authentication, data storage and controls are clarified with your payment and legal consultant.

How does the development process work?

1. 01
   Clarifying the payment flow

   We define the participants, payment types, currencies, commissions, declines, refunds and reports. We review the documentation and test environments of the providers you want to use.

2. 02
   Designing roles and data

   We determine what the customer, merchant, operator, accountant and administrator can see. We create a model for orders, transactions, balances, events and the change log.

3. 03
   Building the server and panels

   We develop the API, administration panel, customer flow and connections to banks and payment providers. We add notification handling, retries, refunds and reports.

4. 04
   Mobile integration and testing

   We connect the app or mobile version to the server. We test approved and declined operations, lost connections, duplicate notifications, expired sessions and refunds.

5. 05
   Launch and monitoring

   We prepare the production configuration, access credentials and backup procedures. We monitor errors and discrepancies between the platform and the provider and resolve them in a traceable way.

What do you need to prepare?

We need a description of the business model, a list of participants, a selected or preferred payment provider, API documentation, test access and payment and refund rules. Sample reports, invoices, bank statements and cases you currently process manually are also useful.

The price for a custom platform is determined within the range €3,000-€29,300. This range covers projects of varying scope involving custom software, ERP and fintech systems. Within the range, the price is affected by the number of payment providers, roles, mobile app, subscriptions, fund allocation, reports, regulatory requirements and the need to connect with an ERP or CRM.

What relevant experience can you review?

For payment processing and financial flows, you can review Crypto.bg, cryptocurrency platform, which describes a platform for buying and selling cryptocurrency with BGN payments. For a separate payment scenario, see Christian Center Sofia, website and donations, which includes card donations through Stripe, monthly partnerships and a custom API for payments.

How can we discuss your platform?

Send us a brief description of your business, payment types, preferred banks or providers and the systems that need to be connected. If you have a process diagram, sample report or API documentation, attach it to your enquiry via the contact form.