Senior Software Engineer (Processor Integrations) in Irvine, California at EBizCharge and Century Business Solutions

Headquartered in Irvine, California, EBizCharge specializes in developing integrated payment solutions that facilitate electronic payment processing within ERP, CRM, Mobile, and eCommerce applications. Our applications are PCI compliant and fully integrated with major ERP/accounting systems, including QuickBooks, Sage, SAP Business One, Microsoft Dynamics, NetSuite, Epicor, Acumatica, and major online shopping carts, including Magento and WooCommerce. EBizCharge offers its employees tremendous learning opportunities, career growth potential, and a dynamic work environment.

At the core of our payments platform is the infrastructure that connects our systems to the payment processors that move money on behalf of our merchants. We are looking for a senior engineer who understands this domain deeply. Someone who has navigated the complexity of processor certification, built reliable integration layers against demanding external APIs, and takes pride in keeping critical financial infrastructure running with precision.

Responsibilities

• Design, build, and maintain robust integrations with card-not-present payment processors and gateways, covering both direct processor connections and third-party gateway platforms such as Stripe, Adyen, and CyberSource, across transaction authorization, capture, void, refund, and settlement flows.
• Manage the full integration lifecycle, from initial specification review and environment setup through certification, production deployment, and ongoing maintenance.
• Navigate processor and gateway certification processes confidently, coordinating test plans and certification scripts with partner technical teams and resolving findings efficiently.
• Handle the nuances of each partner's implementation: field mapping, response code handling, timeout and retry behavior, and edge cases that only surface under real production conditions.
• Monitor integration health proactively, building alerting and diagnostic tooling that surfaces partner-side issues before they impact merchants.
• Design clean, versioned, and well-documented internal APIs that expose processor capabilities to the broader gateway platform in a consistent, processor-agnostic way.
• Build and maintain backend services in C# and .NET that abstract processor-specific complexity behind stable interfaces, enabling other teams to consume payment functionality without coupling to individual processor implementations.
• Participate actively in code reviews, bringing rigorous standards for correctness, reliability, and long-term maintainability to integration-critical code paths.
• Implement robust retry logic, idempotency handling, timeout management, and graceful degradation to ensure transaction integrity across all processor and gateway integrations.
• Serve as a technical resource and mentor for junior and mid-level engineers on the squad, sharing domain knowledge through pair programming, code review, and documentation.

Qualifications

• Strong proficiency in C# and the .NET ecosystem, with a track record of building and operating production-grade backend services in a payments or similarly critical environment.
• Hands-on experience integrating with card-not-present payment processors and/or payment gateways, with a solid understanding of the similarities and differences between direct processor and gateway integration models.
• Demonstrated experience navigating integration certification processes, including coordinating with partner technical teams and managing test scripts and certification artifacts.
• Experience designing and building internal APIs and microservices with a strong emphasis on reliability, versioning, and clean abstraction of external dependencies.
• Solid understanding of PCI DSS requirements as they apply to card-not-present transaction processing, tokenization, and cardholder data handling.
• Direct experience with major payment processors such as TSYS or Fiserv, or payment gateways such as Stripe, Adyen, or CyberSource.
• Familiarity with ISO 8583 messaging or other low-level payment messaging formats used in direct processor communication.
• Understanding of interchange optimization, transaction qualification, and the downstream impact of authorization decisions on merchant costs.
• Familiarity with network tokenization standards and how they interact with processor and gateway authorization flows.

Job Type: Full-time

The Company is committed to compliance with all applicable laws providing equal employment opportunities. This commitment applies to all persons involved in Company operations. The Company prohibits unlawful discrimination against any job applicant, employee, or unpaid intern by any employee of the Company, including supervisors and coworkers. Pay discrimination between employees of the opposite sex or between employees of another race or ethnicity performing substantially similar work, as defined by the California Fair Pay Act and federal law, is prohibited.