Principal Software Engineer (Java)

Powering the world’s payments ecosystem

ACI powers the payments ecosystem – globally, and you power ACI. You’ll innovate, collaborate, and grow – in an energetic technology culture with decades of proven success. ACIers – in all roles and levels – are truly your colleagues and many are your friends. Our size and reach allow you to see the global impact of your work. You are visible, your talents are valued, and you are empowered to shape the future of payments.

As a Principal Software Engineer in Bangalore, you will join a diverse, passionate team, dedicated to powering the world’s payments ecosystem!

Job Summary

ACI Worldwide is seeking a highly experienced Principal Software Engineer to lead the architecture, design, and modernization of enterprise-scale payment solutions. This role is ideal for a hands-on technical leader with deep expertise in Java/J2EE, Spring Boot, Microservices, Cloud Technologies, Angular as UI development and Distributed Systems who can drive technical strategy, influence engineering direction, and mentor development teams across the organization.

Key Responsibilities

• Define and drive architecture, technical strategy, and engineering standards for mission-critical applications.
• Lead the design and development of scalable, secure, and high-performance Java-based enterprise solutions.
• Drive modernization initiatives, including cloud-native and microservices architectures.
• Provide technical leadership across multiple teams and serve as the escalation point for complex architectural challenges.
• Partner with Product, Engineering, and Business stakeholders to align technology investments with business objectives.
• Mentor senior engineers and promote engineering excellence, innovation, and best practices.

Required Qualifications

• Bachelor's degree in Computer Science or related field.
• 10+ years of software engineering experience with proven technical leadership.
• Extensive experience designing and delivering large-scale enterprise applications.
• Strong experience leading architecture and development across multiple teams.
• Experience in Payments, Financial Services, FinTech, or other regulated industries preferred.

Technical Expertise

• Expert-level experience with Java, J2EE/Jakarta EE, Spring, Spring Boot, Hibernate/JPA.
• Deep expertise in Microservices Architecture, REST APIs, Event-Driven Systems, and Distributed Computing.
• Strong knowledge of Cloud Platforms (AWS/Azure/GCP), Docker, Kubernetes/OpenShift, and CI/CD practices.
• Experience with Kafka, Messaging Frameworks, API Gateways, and High-Volume Transaction Processing Systems.
• Experience with Angular as UI development
• Strong understanding of application security, scalability, performance optimization, and reliability engineering.
• Experience evaluating and adopting emerging technologies, including AI-powered engineering tools.

AI & Emerging Technologies

• Proven experience evaluating and integrating AI/ML capabilities into enterprise applications and platforms.
• Strong understanding of Generative AI, Large Language Models (LLMs), Retrieval-Augmented Generation (RAG), AI agents, and prompt engineering concepts.
• Experience designing and consuming AI-powered APIs and services (e.g., Azure AI, OpenAI, AWS AI Services).
• Ability to identify business use cases where AI can improve customer experience, operational efficiency, product capabilities, and engineering productivity.
• Experience establishing governance, security, privacy, and responsible AI practices for enterprise solutions.
• Demonstrated use of AI-assisted development tools (GitHub Copilot, Cursor, AI coding assistants, etc.) to accelerate software delivery and improve code quality.
• Ability to drive technical strategy and architectural decisions related to AI adoption across engineering organizations.

Professional Skills

• Exceptional communication and stakeholder management skills.
• Strong architectural thinking with a business-outcome mindset.
• Ability to influence technical direction without direct authority.
• Passion for mentoring and developing engineering talent.

Preferred Qualifications

• Experience building enterprise payment processing or financial technology platforms.
• Cloud certifications and enterprise architecture experience.
• Proven track record of leading large-scale modernization and digital transformation initiatives.
• Industry thought leadership, publications, patents, or conference speaking experience.

Ideal Candidate

The ideal candidate combines deep expertise in Java/J2EE, Microservices, Cloud, and Distributed Systems with the ability to architect and scale AI-enabled enterprise solutions, driving innovation while ensuring security, reliability, and business value.

Core Capabilities

We seek colleagues who embody our core capabilities — these shape our culture and enable us to make a meaningful impact together:

• Ensure Accountability: holding self and others accountable to meet commitments.

• Drives Results: consistently achieving results, even under tough circumstances.

• Customer Focus: building strong customer relationships and delivering customer-centric solutions.

• Cultivate Innovation: creating new and better ways for the organization to be successful.

• Collaborates: building partnerships and working collaboratively with others.

• Courage: stepping up to address difficult issues, saying what needs to be said.

In return for your expertise, we offer opportunities for growth, career development, and a competitive compensation and benefits package—all within an innovative and collaborative work environment.

Are you ready to help us transform the payments ecosystem? To learn more about ACI Worldwide, visit our web site at

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