Senior Software Engineer – Payments (Credit Card & Alternative Payments)

Location: Serbia Workplace: remote ABOUT YOU We are seeking a highly skilled Senior Software Engineer – Payments to design, build, and maintain core components of our payment processing platform — spanning both credit card acquiring and alternative payment methods (APMs). Working closely with the Tech Lead and cross-functional partners in Product, Finance, and Risk, you will take ownership of critical payment flows across the full ecosystem: from real-time card authorization through clearing, settlement, and reconciliation, to wallets, bank transfers, local payment methods, and beyond. This role is for an engineer who thrives in complex, high-stakes financial systems, cares deeply about data integrity, and brings both the technical depth and collaborative instincts to contribute meaningfully across the full payments stack. ABOUT US Xsolla is a global commerce company with robust tools and services to help developers solve the inherent challenges of the video game industry. From indie to AAA, companies partner with Xsolla to help them fund, distribute, market, and monetize their games. Grounded in the belief in the future of video games, Xsolla is resolute in the mission to bring opportunities together, and continually make new resources available to creators. Headquartered and incorporated in Los Angeles, California, Xsolla operates as the merchant of record and has helped over 1,500+ game developers reach more players and grow their businesses around the world. For more information, visit xsolla.com. RESPONSIBILITIES Credit Card Payment Processing Implement and maintain scalable, fault-tolerant services handling real-time authorization, batch clearing, and settlement workflows. Build and maintain integrations with acquiring banks, card networks (Visa, Mastercard, Amex, Discover), payment gateways, fraud providers, and tokenization services. Implement resilient routing logic, retry strategies, and failover mechanisms across card network connections. Ensure transaction idempotency and correct state management across the full card payment lifecycle. Support 3D Secure (3DS2) and Strong Customer Authentication (SCA) flows. Implement and maintain card vaulting and tokenization solutions in line with PCI DSS requirements. Alternative Payment Methods (APMs) Build and maintain integrations with a broad range of APMs, including digital wallets (PayPal, Apple Pay, Google Pay), bank transfers (ACH, SEPA, instant bank pay), buy now pay later (BNPL) providers, prepaid and voucher methods, and regional local payment methods across key markets. Design flexible, extensible integration patterns that allow rapid onboarding of new payment methods and providers. Handle the unique lifecycle requirements of each payment method — including asynchronous notifications, delayed confirmations, refund flows, and currency/settlement nuances. Collaborate with Product to evaluate and prioritize new APM integrations based on market coverage and player demand. Reconciliation & Financial Integrity Build and maintain automated reconciliation pipelines that match authorization, clearing, and settlement records across both card and APM payment rails. Reconcile internal ledgers against acquirer, network, and PSP reports; detect and surface mismatches, duplicates, and missing transactions. Develop safeguards to prevent revenue leakage and ensure ledger consistency at scale. Ensure all financial systems are audit-ready and compliant with internal financial controls. Reporting, Monitoring & Alerting Build and maintain payment reporting systems covering authorization rates, settlement reconciliation, interchange and fee breakdowns, APM conversion rates, and chargeback/dispute metrics. Implement threshold-based alerting for authorization rate drops, decline pattern anomalies, settlement mismatches, volume spikes, and chargeback ratio changes across all payment methods. Contribute to internal financial dashboards supporting cost optimization, risk monitoring, and financial performance visibility. Participate in on-call rotations and incident response for payment-critical systems. Compliance & Security Build systems compliant with PCI DSS , card network operating regulations, data encryption and tokenization standards, and regional mandates. Contribute to secure handling of sensitive payment data across card and APM flows. Support audit processes and financial compliance reviews as required. Fraud & Dispute Management Integrate with fraud detection and risk scoring systems across card and APM payment flows. Implement chargeback and dispute workflow components, including evidence submission and representment support. Build safeguards and monitoring for fraud pattern detection across payment methods. Engineering Excellence Write clean, well-tested, well-documented code with a strong focus on reliability, observability, and correctness. Participate actively in code reviews, technical design discussions, and architecture decisions. Contribute to best practices for distributed systems design, observability, incident response, and financial data integrity. Mentor junior engineers and contribute to a high-trust, high-accountability engineering culture. QUALIFICATIONS & SKILLS 5+ years of software engineering experience, with a strong focus on PHP and Go (Golang) tech stacks at least 2+ years working on payment processing systems in production Hands-on experience with card payment flows: authorization, clearing, settlement, reconciliation, and chargebacks. Experience integrating with or building against one or more APM providers (wallets, bank transfers, BNPL, local payment methods). Solid understanding of the four-party (Visa/Mastercard) and three-party (Amex/Discover) models , including interchange, BIN logic, MCC codes, AVS, CVV, and 3DS/SCA. Strong understanding of distributed systems: idempotency, eventual consistency, fault tolerance, and high availability. Proficiency in designing and consuming RESTful and/or event-driven APIs in a payments context. Familiarity with PCI DSS and payment data security fundamentals. Strong debugging and incident response skills in complex, high-volume financial systems. NICE TO HAVE Experience at a PSP, acquirer, issuer, payment gateway, or fintech platform. Familiarity with global payments and cross-border processing, including FX, local settlement, and regulatory considerations. Experience at high transaction volumes (10M+ monthly transactions). Exposure to authorization rate optimization and intelligent payment routing. Familiarity with the gaming, digital goods, or e-commerce payments landscape. Experience with audit processes and financial compliance reviews. WHAT SUCCESS LOOKS LIKE In your first 6 months, you will have: Delivered meaningful improvements to at least one area of the card or APM payment stack — whether a new integration, a reconciliation improvement, or a reliability/observability uplift. Demonstrated deep ownership of a payment domain area, proactively identifying and resolving gaps in reliability, correctness, or coverage. Built strong working relationships with the Tech Lead, PM, and cross-functional stakeholders across Finance and Risk. Contributed to engineering practices that raise the quality bar for the broader payments team. Benefits   We are passionate about fostering a supportive environment for our team, so we prioritize the physical, mental, and emotional well-being of our employees through a comprehensive Benefits Program. This includes unlimited Flexible Time Off and a personalized career roadmap for each employee. By investing in professional development through training and educational opportunities, we ensure that our team thrives both personally and professionally. Together, we’re not just building a business; we’re cultivating a community that values creativity, collaboration, and the transformative power of play.   The duties and responsibilities of this position may evolve over time to support the organization’s goals and individual growth. This job description is intended to outline the general nature and level of work being performed and is not intended to be an exhaustive list of all duties, responsibilities, and qualifications required.   By submitting your application, you consent to Xsolla conducting background checks, where permitted by law, after the final interview stage. All checks will comply with local regulations, and your information will be handled confidentially.   Xsolla takes your privacy seriously and will not sell or externally distribute any personal data received during the hiring process. In accordance with applicable data protection laws, Xsolla is committed to protecting your personal information and respecting your privacy.   For any inquiries related to data privacy, please contact: careers@xsolla.com    Explore more opportunities at: https://xsolla.com/careers