Sr Software Engineer

ACI Worldwide; Limerick; On-site; EUR 90,000 - 120,000; Full time

Job summary

ACI Worldwide is seeking an experienced Senior Software Engineer to join the MTS Development team responsible for a critical high-value payments platform. This role focuses on maintaining, enhancing, and modernizing core payment processing capabilities while supporting regulatory mandates, customer commitments, platform resiliency, and long-term product sustainability.

The ideal candidate will have experience in complex enterprise applications, payment systems, production support, and

Qualifications

• 8+ years of software development experience.
• Strong Java and enterprise application development experience.
• Experience with large-scale transaction processing platforms.
• Experience debugging complex production issues.
• Strong understanding of software architecture, integration patterns, APIs, and database technologies.
• Experience with secure software development practices.
• Excellent communication and collaboration skills.

Responsibilities

• Design, develop, and maintain core MTS platform capabilities.
• Deliver customer and regulatory commitments including payment network mandates.
• Participate in production issue resolution and root cause analysis.
• Support modernization initiatives including 64-bit migration, ISO 20022, structured address, security, and platform enhancement programs.
• Collaborate with Product Management, Professional Services, Quality Engineering, and Customer Support teams.
• Act as a technical mentor and support knowledge transfer initiatives.
• Drive engineering excellence through automation, testing, observability, and quality improvements.
• Leverage AI-assisted engineering tools to improve productivity and code quality.

Skills

Java

Enterprise apps

Transaction processing

Production debugging

Software architecture

APIs & integration patterns

Databases

Secure SDLC

Communication

Job description

Position Summary

We are seeking an experienced Senior Software Engineer to join the MTS Development team responsible for one of the industry's most critical high-value payments platforms. This role will focus on maintaining, enhancing, and modernizing core payment processing capabilities while supporting regulatory mandates, customer commitments, platform resiliency, and long-term product sustainability.

The ideal candidate will be a strong software engineer with experience in complex enterprise applications, payment systems, mission-critical production support, and large-scale modernization initiatives.

Key Responsibilities

• Design, develop, and maintain core MTS platform capabilities.
• Deliver customer and regulatory commitments including payment network mandates.
• Participate in production issue resolution and root cause analysis.
• Support modernization initiatives including 64-bit migration, ISO 20022, structured address, security, and platform enhancement programs.
• Collaborate with Product Management, Professional Services, Quality Engineering, and Customer Support teams.
• Act as a technical mentor and support knowledge transfer initiatives.
• Drive engineering excellence through automation, testing, observability, and quality improvements.
• Leverage AI-assisted engineering tools to improve productivity and code quality.

Required Qualifications

• 8+ years of software development experience.
• Strong Java and enterprise application development experience.
• Experience working with large-scale transaction processing platforms.
• Experience debugging complex production issues.
• Strong understanding of software architecture, integration patterns, APIs, and database technologies.
• Experience with secure software development practices.
• Excellent communication and collaboration skills.

Preferred Qualifications

• Payments industry experience (Fedwire, CHIPS, SWIFT, ISO 20022).
• Experience supporting Tier-1 financial institutions.
• Experience with cloud migration and modernization initiatives.
• Knowledge of high-availability and mission-critical systems.
• Experience using AI engineering tools such as Copilot, Cursor, Claude, or equivalent.

Success Measures

• Successful delivery of roadmap and mandate commitments.
• Reduction in production incidents and resolution time.
• Increased automated test coverage.
• Effective knowledge transfer and documentation.
• Contribution to long-term platform sustainability.