Haya M.

I design and build fintech products end to end: from card authorization to settlement, from merchant onboarding to the ledger. Payment infrastructure: • Payment gateway: card acceptance, 3D Secure flows, SCA exemption engine, acquirer integrations • Card processing: authorization, capture, refund, installments, BIN-based routing • Payment orchestration (switch): cost-based routing across multiple PSPs and banks (debit / credit / foreign cards, on-us) • Issuer-side systems: card issuing, card lifecycle, limits Money movement & accounting: • Digital wallets: balances, top-up, transfers, payouts to IBAN • Double-entry ledger: journal, trial balance, balance sheet, income statement • Settlement and reconciliation, merchant payouts, webhooks with retry and dead-letter queue Risk & compliance: • Fraud and risk engine: rule-based scoring, BIN intelligence, velocity checks • KYC / KYB onboarding: individual and business merchants, document flows • Sanctions screening, audit trails, PCI-DSS-aware architecture (tokenization, minimal card data scope) Products: • Merchant back-office and admin panels: merchants, transactions, refunds, settlements, reports • Mobile and web apps for wallet and payment users Tech: Go, TypeScript, Next.js, Node.js, PostgreSQL, NATS, Docker, Prisma, Cloudflare I work with fintech startups, PSPs and marketplaces that need a payment system that is correct, auditable and ready for regulators. Send me your project. I will reply with a short technical plan and an estimate.