Payment Platform Development

Payment acquiring follows a three-party flow: the cardholder's issuing bank authorises the transaction, the card network (Visa, Mastercard, Amex) routes the message, and the acquirer settles funds to the merchant. Your platform sits above this flow, using Stripe, Adyen, Checkout.com, Braintree, or regional acquirers as the acquiring layer. Each processor exposes an SDK or REST API for payment intent creation, authorisation capture, refund initiation, and webhook delivery of transaction lifecycle events.

Multi-provider routing is implemented as a configurable rule engine: route by card BIN range (to optimise for domestic interchange rates), by transaction amount (high-value transactions may warrant a different processor with lower basis point fees), by currency, or by merchant category code (MCC). Automatic failover switches to the secondary processor when the primary returns a terminal error code (network failure, processor downtime) -- preserving the transaction rather than presenting an error to the customer. All payment intent creation calls include an idempotency key (UUID v4, stored per session) so network retries never produce duplicate charges. Webhook delivery from processors uses HMAC-SHA256 signature verification to confirm each event is genuine before updating your order state. The acquiring layer gives you redundancy, interchange optimisation, and the ability to add a new processor to your routing rules without changing application code.

Web and mobile checkout built for your specific conversion goals. Returning customers with stored payment methods see a one-click checkout flow that skips card entry entirely; the tokenised card-on-file is charged directly via the processor's tokenisation vault, with the card number never passing through your servers. New customers get a guest checkout path with no forced account creation -- the most common conversion killer in generic checkout flows.

3D Secure 2.0 (EMV 3DS) authentication is integrated for strong customer authentication (SCA) under PSD2 for European transactions. Dynamic 3DS triggering applies friction only when the transaction risk score warrants it -- low-risk transactions from known devices are exempted, preserving conversion on clean traffic. Card details are captured using processor-hosted fields (Stripe Elements, Adyen Drop-in, Braintree Hosted Fields) so raw card data never touches your application layer, keeping PCI DSS scope to SAQ A or SAQ A-EP. Address autocomplete via Google Places API reduces input errors and improves speed. Real-time card BIN lookup validates card type and issuer country as the customer types, enabling instant dynamic routing decisions. Checkout state is persisted so customers returning to an abandoned session resume from where they left off. A/B testing hooks allow your growth team to test checkout variants -- field order, CTA copy, payment method display order -- without engineering involvement on each experiment.

Multi-currency payment infrastructure for international businesses operating across more than one currency zone. Live FX rates sourced from ECB (European Central Bank) reference rate feeds or a commercial FX data provider such as Open Exchange Rates, with configurable spread added to the mid-market rate to cover your FX cost. Prices are displayed in the customer's local currency at checkout; payment is accepted in that currency; settlement flows to your base currency account with conversion applied at point of sale or deferred to the daily settlement batch, depending on your FX exposure preference.

Currency-specific local payment method routing extends beyond card: iDEAL for Netherlands, SEPA Direct Debit and SEPA Credit Transfer for European bank payments, BACS Direct Debit for UK recurring charges, UPI for India, Pix for Brazil, OXXO for Mexico cash payments. Each payment rail has its own API integration, settlement timeline, and refund mechanics. ACH (Automated Clearing House) for US bank transfers and NACHA-compliant file formatting for batch ACH origination. SEPA batch initiation follows the SEPA pain.001 XML schema for credit transfers. Rail selection and local method availability are configured per currency and market, so you do not offer iDEAL to a US customer or ACH to a German customer. FX spread and rate display configuration let your commercial team set the margin and choose whether to show the exchange rate to customers explicitly. Multi-currency reconciliation maps each foreign currency transaction back to your base currency ledger entry with the applied rate recorded, so your finance team closes the books without manual currency conversion calculations.

Marketplace payment infrastructure built on Stripe Connect (standard or custom accounts) or Adyen Platforms, depending on your payout model and the level of control you need over the seller experience. The PayFac (Payment Facilitator) model -- where your platform is the merchant of record -- is distinct from a payment aggregation model where sellers onboard directly with the processor; we scope the right model based on your regulatory appetite, seller onboarding friction requirements, and payout timeline needs.

Seller onboarding includes KYC identity verification (government ID, address, date of birth) and bank account or debit card verification before the first payout is released. Stripe Connect handles the identity verification flow via their hosted onboarding UI, or we build a custom flow using their API if your brand consistency requirements demand it. Commission and platform fee deduction is configurable per transaction and per seller tier -- flat percentage, flat fee, or a combination. Automated payout scheduling runs daily, weekly, or on-demand with a configurable payout hold period to protect against chargebacks on recently-settled transactions. 1099-K tax document generation for US sellers is handled via Stripe Tax or Adyen's reporting API at year end. Seller dashboard shows transaction history, pending payout amounts, scheduled payout dates, and account verification status. The split payment layer removes the manual reconciliation work that marketplace operators typically carry before this is built -- matching processor settlement reports to individual seller accounts in spreadsheets -- and replaces it with an automated ledger that closes every day without intervention.

Automated daily reconciliation between payment processor settlement reports and your internal ledger. Each processor delivers a settlement file (CSV, JSON, or SFTP batch) at end of day containing the transactions included in the settlement payout and any fees deducted. The reconciliation engine ingests these files, matches each line item against your internal transaction records by payment intent ID or processor transaction reference, computes the expected payout amount, and compares it against the actual payout. Exceptions -- missing transactions, fee discrepancies, amount mismatches -- are flagged in a reconciliation dashboard for your finance team to review and resolve, rather than requiring them to comb through the raw settlement file.

Transaction-level audit trail covers all payment lifecycle events: payment intent created, card authorised, funds captured, partial or full refund initiated, refund settled, dispute (chargeback) opened, evidence submitted, dispute resolved. Every event is timestamped, processor-referenced, and associated with the originating order in your system. Webhook delivery from processors is received over HTTPS with HMAC-SHA256 signature verification and processed idempotently -- duplicate webhook deliveries (common in high-volume environments) do not create duplicate records. Finance team dashboard shows gross payment volume, net settlement after processor fees, refund rate, dispute rate, and average transaction value by day, week, and month. Exportable to CSV for accounting system import. The reconciliation layer closes the books cleanly every day without your finance team building the bridge between processor reports and your general ledger manually.

Fraud controls built around the transaction risk signal available at checkout. 3D Secure 2.0 (EMV 3DS) authentication is integrated with dynamic challenge triggering: low-risk transactions from known devices and established cardholders are exempted from the 3DS challenge under PSD2's Transaction Risk Analysis (TRA) exemption, preserving conversion on clean traffic; high-risk transactions are stepped up to 3DS challenge before authorisation. This avoids the blanket 3DS friction that kills conversion for good customers while retaining authentication for genuinely risky transactions.

Velocity rules run server-side at transaction evaluation: maximum attempts per card number in a rolling window, per email address, per IP address, and per device fingerprint. Device fingerprinting using browser and hardware attributes identifies returning fraud devices across different card numbers -- a common card testing pattern. Fraud scoring integration with Stripe Radar rules, Kount, or Sardine risk API provides a machine learning fraud score that factors in IP reputation, device intelligence, email risk, and behavioural signals. Score thresholds are configurable: block at high confidence, review queue at medium confidence, pass through at low risk. PCI DSS scope reduction is achieved by using processor-hosted card capture fields (Stripe Elements, Adyen Drop-in), ensuring card data never touches your servers. This reduces your PCI scope to SAQ A or SAQ A-EP and removes the need for annual PCI Level 1 QSA audit for most implementations. Chargeback dispute management workflow captures order evidence (delivery confirmation, customer communication, refund policy acceptance) and submits it to the processor within the dispute response window. Dispute rate monitoring alerts when the platform's ratio approaches the processor's threshold (typically 0.9% for Mastercard, 1% for Visa) before it triggers a formal compliance programme.