Software Engineer II

Mastercard is seeking a Software Engineer II to join the Transaction Stream team. The team delivers next-generation Core Payment capabilities for Mastercard using modern digital architecture, cloud-native principles, event-driven technologies, and a Scaled Agile delivery framework.

As a Software Engineer II, you will contribute to the delivery and quality of payment-processing capabilities across highly integrated systems. You will apply strong payments domain knowledge and technical expertise to understand business requirements, analyse transaction flows, validate end-to-end system behaviour, and ensure capabilities work effectively across the broader payment ecosystem.

Responsibilities:

• Contribute to the design, delivery, validation, and quality of Transaction Stream and Mastercard payment-processing capabilities.
• Apply strong functional and technical domain knowledge to understand requirements, solution designs, transaction flows, and expected system behaviour.
• Translate business and technical requirements into end-to-end functional scenarios, integration scenarios, expected outcomes, and validation coverage.
• Perform hands-on functional and end-to-end integration validation across interconnected systems, applications, APIs, services, and payment-processing platforms.
• Analyse complex payment transaction flows across authorization, advice, reversal, clearing, and related payment-processing lifecycle scenarios.
• Validate system behaviour across upstream and downstream components to ensure solutions function correctly across integration boundaries.
• Analyse ISO payment messages, application logs, system responses, APIs/interfaces, and data flows to troubleshoot functional and integration issues.
• Identify software defects, functional gaps, integration issues, dependencies, and potential customer impact through detailed analysis of system interactions and transaction behaviour.
• Work closely with Software Engineering, Product, Business, Architecture, and dependent application teams to investigate issues and drive them to resolution.
• Support defect investigation and root-cause analysis by tracing transactions across multiple applications and identifying the component or integration point associated with unexpected behaviour.
• Contribute to automation, utilities, frameworks, and self-service tooling that improve validation coverage, repeatability, efficiency, and engineering productivity.
• Participate in requirement walkthroughs, solution and design reviews, code/implementation discussions, and release-readiness activities, providing an end-to-end payments and integration perspective.
• Analyse production issues and customer-reported scenarios to reproduce problems, identify gaps, and contribute to improvements in application quality and resilience.
• Support continuous improvement of engineering practices, integration coverage, observability, troubleshooting approaches, and overall software quality.
• Collaborate effectively with globally distributed Engineering, Product, Architecture, Business, and dependent technology teams in an Agile delivery environment.

Requirements:

• Bachelor's or master's degree in Computer Science, Information Technology, Engineering, or equivalent practical experience.
• Experience working with complex transactional platforms, payment-processing systems, or highly integrated enterprise applications.
• Strong knowledge of the cards and payments domain, including transaction lifecycle, message flows, processing rules, and system interactions.
• Hands-on knowledge of authorization, advice, reversal, clearing, and related payment-processing flows.
• Working knowledge of payment messaging standards such as ISO 8583 and ISO 20022.
• Strong experience in functional, system, and end-to-end integration validation across distributed applications and interconnected systems.
• Ability to translate business and technical requirements into functional scenarios, transaction flows, integration scenarios, expected outcomes, and validation coverage.
• Strong analytical and troubleshooting skills with the ability to investigate complex issues across multiple applications, services, and integration points.
• Ability to analyse transaction messages, application logs, APIs/interfaces, system responses, and data to understand application behaviour and isolate issues.
• Familiarity with payment simulation or transaction-generation tools such as T3 or equivalent tools.
• Good understanding of modern software architecture, including microservices, APIs, cloud platforms, event-driven architecture, caching, and persistence technologies.
• Familiarity with CI/CD pipelines, source-control practices, automated validation, and modern software delivery processes.
• Working knowledge of Java, Spring Boot, APIs, SQL, scripting, or similar technologies to support application analysis, troubleshooting, automation, and integration validation.
• Experience developing or contributing to automation, utilities, test harnesses, API-based validation, or engineering tools that improve quality and delivery efficiency is preferred.
• Understanding of software engineering principles, including debugging, defect analysis, root-cause analysis, maintainability, reliability, and observability.
• Strong communication and collaboration skills with the ability to work across Engineering, Product, Business, Architecture, and dependent technology teams.
• Comfortable working in an Agile software delivery environment.