Software Engineer II

Our Purpose
Mastercard powers economies and empowers people in 200+ countries and territories worldwide. Together with our customers, we're helping build a sustainable economy where everyone can prosper. We support a wide range of digital payments choices, making transactions secure, simple, smart and accessible. Our technology and innovation, partnerships and networks combine to deliver a unique set of products and services that help people, businesses and governments realize their greatest potential.
Title and Summary
Software Engineer II
Overview
The Mastercard Transaction Stream team is involved in delivering next-generation Core Payment capabilities for Mastercard. These solutions are built using modern digital architecture, cloud-native principles, event-driven technologies, and a Scaled Agile delivery framework.
As a Software Engineer II within the Transaction Stream team, 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.
The role requires hands-on involvement in functional and end-to-end integration validation, combined with a strong understanding of cards and payments, transaction switching, ISO payment messaging, system interfaces, and distributed application architectures.
You will work closely with Engineering, Product, Architecture, and dependent technology teams to identify integration gaps, troubleshoot complex transaction scenarios, and support reliable delivery of Transaction Stream capabilities.
The Role
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.
All About You
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.
Corporate Security Responsibility
All activities involving access to Mastercard assets, information, and networks comes with an inherent risk to the organization and, therefore, it is expected that every person working for, or on behalf of, Mastercard is responsible for information security and must:

• Abide by Mastercard's security policies and practices;
• Ensure the confidentiality and integrity of the information being accessed;
• Report any suspected information security violation or breach, and
• Complete all periodic mandatory security trainings in accordance with Mastercard's guidelines.