Payment Systems & Fintech Integration
Every new payment method your platform needs to support becomes new bespoke code. Every gateway you add is another place a transaction can silently fail, double-charge a customer, or get lost between your systems and the provider's. Most teams find this out in production, on live traffic, with a finance team asking why the numbers don't reconcile.
What we build
- Multi-gateway integration and abstraction layer
- Card processing (Visa/Mastercard) — authorization, capture, settlement
- Mobile financial services (MFS) integration
- Bank-issued EMI and instalment flows
- Subscription and recurring billing
- Webhook/IPN handling with signature verification
- Idempotency and duplicate-transaction protection
- Reconciliation and settlement matching
- Refunds, partial refunds, and chargeback handling
- PCI scope reduction via tokenization
- Full audit trails on every transaction state change
- Explicit failure-mode and retry handling
Technical approach
Gateway integration and abstraction
A single internal payment interface with a provider adapter per gateway, so your checkout, order, and fulfilment logic never depend on any one provider's API shape. Adding a new payment rail means writing an adapter, not rewriting your business logic.
Card processing (Visa/Mastercard)
Direct integration with card-network-compliant gateways for authorization, capture, and settlement, built around your specific card-present or card-not-present flow.
Mobile financial services integration
Mobile financial service providers use different confirmation models than card networks — different timing, different failure signals. We integrate MFS rails under the same abstraction layer as card processing, so reconciliation and reporting don't fork per payment method.
EMI and instalment flows
Bank-issued equated monthly instalment (EMI) plans with correct tenure, eligibility, and interest-handling logic, integrated against participating banks' EMI APIs.
Subscription and recurring billing
Tokenized recurring charge schedules, dunning logic for failed renewals, and proration for mid-cycle plan changes.
Webhook/IPN handling
Payment state is never trusted from a client-side redirect. Every transaction status change is confirmed server-to-server via webhook or IPN, with provider signatures verified before the event touches your order state.
Idempotency and duplicate-transaction protection
Every transaction carries an idempotency key. Duplicate webhook deliveries, network retries, and accidental double-submits resolve to the same transaction record — never a duplicate charge or duplicate fulfilment.
Reconciliation and settlement matching
Internal transaction records are matched against provider settlement reports on a scheduled basis, surfacing discrepancies — missing settlements, amount mismatches, unexpected fees — before they become a finance-team fire drill.
Refunds, partial refunds, and chargebacks
Full and partial refund flows that keep your internal ledger consistent with the gateway, plus a defined process for chargeback evidence submission and dispute tracking.
PCI scope reduction via tokenization
We never store raw card data. Card details are tokenized at the gateway or via a PCI-compliant vault, so your infrastructure handles tokens, not primary account numbers — substantially reducing your PCI DSS scope.
Audit trails
Every state transition on a transaction — created, authorized, captured, settled, refunded, disputed — is recorded with enough context to answer "what happened to this payment, and when" without digging through application logs.
Failure modes and retry strategy
Gateway timeouts, partial failures, and provider outages are explicit, handled states, not silent errors. Retries are bounded and idempotent, so a slow provider response never produces a duplicate transaction.
Related work
BRAC Otithi E-Commerce
Tour booking e-commerce platform supporting multiple packages per city with integrated Cybersource and PortPOS payment gateways
100+ transactions daily
Architecture and full-stack engineering delivered for BRAC by our lead engineer.
Engagement model
Payment integration work is typically scoped as a fixed-price project once we've mapped your existing gateways, providers, and compliance requirements. For platforms with an evolving payment surface — new markets, new rails — we also offer a monthly retainer.
Indicative starting price ranges are pending final confirmation from the team. See /pricing for engagement models once published.
Frequently asked
- Do you store card data?
- No. Card data is tokenized at the gateway or a PCI-compliant vault — our systems only ever handle tokens, never primary account numbers.
- Which gateways and providers have you integrated?
- Our engineers have integrated Cybersource and PortPOS in production, alongside mobile financial services and bank EMI providers. See our payment gateway integration case study for the full architecture.
- How do you prevent double-charging on retries?
- Idempotency keys on every transaction. Duplicate webhook deliveries or client-side retries resolve to the same transaction record instead of a new charge.
- Can you support bank EMI and instalment payments?
- Yes — bank-issued EMI plans with correct tenure and eligibility handling are part of our standard payment layer.