Payment & Billing Systems Engineer

KORE1, a nationwide provider of staffing and recruiting solutions, has an immediate opening for a Payment & Billing Systems Engineer that is fully remote. Overview This role is focused on building and maintaining reliable, scalable payment and billing systems that directly impact revenue and customer experience. You will take ownership of the full payment lifecyclefrom transaction processing to subscription management and financial reconciliationensuring accuracy, resilience, and security across all billing workflows. This is a high-impact position requiring hands-on experience with real-world payment systems and the ability to design solutions that handle complexity, edge cases, and scale. What You'll Do Own and manage the full payment ecosystem, including primary processors and alternative payment methods Design and maintain subscription lifecycle logic, including activation, upgrades, downgrades, cancellations, and recovery flows Build robust webhook processing systems with strong guarantees around idempotency, ordering, and retry handling Develop reconciliation processes across multiple timeframes, incorporating audit trails and anomaly detection Implement workflows for refunds, chargebacks, and dispute resolution Ensure system reliability through comprehensive test coverage, including integration and end-to-end testing of payment flows Design and enforce fraud detection mechanisms and rate-limiting strategies Maintain and enhance payment security practices, including compliance with industry standards What We're Looking For Proven experience building and deploying payment or billing systems in production environments Strong understanding of the full payment lifecycle, including authorization, capture, settlement, refunds, and reconciliation Deep knowledge of subscription-based systems and common failure scenarios (e.g., webhook race conditions, retries, partial failures) Experience designing financial reconciliation systems, including ledger patterns and audit logging Strong backend development skills using Node.js and TypeScript Experience working with asynchronous processing systems and background job workflows Ability to independently own and deliver complex, high-risk systems Required Experience (Non-Negotiable) Direct, hands-on experience working with Authorize.net in a production environment, including APIs related to transactions, subscriptions, and customer data management Experience building a payment system end-to-end that processes real transactions from real users Nice to Have Experience integrating cryptocurrency payment systems (e.g., Solana, Ethereum, Polygon) Familiarity with PCI compliance standards and secure payment handling practices Experience with modern backend frameworks such as NestJS Technology Stack Authorize.net and related payment APIs Web3 libraries for crypto payments Node.js / TypeScript NestJS PostgreSQL, Redis Temporal or similar workflow orchestration tools Compensation depends on experience but is typically $175K - $195K DOE ABOUT KORE1 Specializing in professional and technical recruiting, KORE1 is committed to supporting top IT, Engineering, Creative, Scientific, Accounting and Finance professionals in their career paths. We build deep relationships with leading companies, connecting them to exceptional talent every day. With extensive industry expertise and unmatched opportunities, our goal is to provide a unique experience for our contractors and consultants as they prepare for their next role. We are passionate about matching the right people with the right companies. Kore1 provides equal employment opportunities (EEO) to all employees and applicants for employment without regard to race, color, religion, sex, national origin, age, disability or genetics. In addition to federal law requirements, Kore1 complies with applicable state and local laws governing nondiscrimination in employment in every location in which the company has facilities. This policy applies to all terms and conditions of employment, including recruiting, hiring, placement, promotion, termination, layoff, recall, transfer, leaves of absence, compensation and training. Kore1 expressly prohibits any form of workplace harassment based on race, color, religion, gender, sexual orientation, gender identity or expression, national origin, age, genetic information, disability, or veteran status. Improper interference with the ability of Kore1's employees to perform their job duties may result in discipline up to and including discharge.