Sr Software Engineer

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. 

Job Summary:  
  

Owns the validation of non-functional requirements across a distributed payments platform, including performance, scalability, availability, and integrity for high-value and instant payment transactions. Designs and runs performance tests, analyzes results, and addresses risks. Partners closely with architects and other engineers to ensure the platform is ready and performs at scale. 
  

Job Responsibilities:  

• Define and validate non-functional requirements - performance, scalability, throughput, latency, availability/HA, and data integrity - in partnership with Product, Architecture, and feature teams 

• Design, build, and maintain test suites using JMeter (or evolving tooling) - load tests, stress tests, soak tests, endurance tests, and capacity benchmarks 

• Execute tests against realistic payment workloads modeled on production transaction patterns (wire transfers, instant payments, A2A flows) 

• Analyze results to identify bottlenecks, regressions, resource constraints, failover gaps, and data consistency risks across services, messaging layers, and data stores 

• Validate availability and resilience — test failover behavior, recovery times, and degradation characteristics under fault conditions 

• Verify data integrity under load - confirm that transactions, state changes, and downstream effects remain consistent at scale 

• Produce clear, professional reports with findings, visualizations, and recommendations - some of which may be shared with customers to support sizing and infrastructure decisions 

• Establish baselines and track trends across releases to detect regressions early and inform capacity planning 

• Collaborate with feature teams to diagnose and address performance issues - profiling, tuning JVM-based services, and validating fixes 

• Contribute to NFR standards - help ensure alignment with target thresholds for latency, throughput, error budgets, recovery objectives, and data consistency across the platform 

• Support go-live readiness by confirming systems meet NFR criteria before customer onboarding milestones 

• Explore future-state integration of performance validation into CI/CD pipelines as the platform and testing practices mature 

• Researches and resolves reported systems software problems efficiently and accurately while adhering to internal software management standards and procedures.   

• Maintains detailed knowledge of software, underlying network and system software, and dependencies.   

• Provides guidance and subject matter expertise to the development organization.  

• Perform other duties as assigned  

• Understand and adhere to all corporate policies to include but not limited to the ACI Code of Business Conduct and Ethics.  

Knowledge, Skills and Experience required for the job: 

• 5+ years of experience in software engineering, performance engineering, QA engineering, or a similar hands-on technical role 

• Demonstrated experience designing and executing performance and load tests for distributed systems 

• Proficiency with JMeter or comparable performance testing tools (Gatling, k6, Locust) 

• Strong analytical skills — ability to interpret test data, isolate bottlenecks across services, and translate findings into clear engineering recommendations 

• Proficiency in Java and familiarity with profiling and tuning JVM-based applications 

• Strong written communication — you'll produce reports consumed by engineers, product managers, leadership, and customers 

• Comfort navigating complex, multi-service architectures to understand system behavior under load 

• Bachelor's degree in computer science or related field or equivalent software development experience.   

• Experience with observability tooling (OpenTelemetry, Grafana) for correlating application metrics with test outcomes 

• 5 years software development experience.  

Preferred Knowledge, Skills and Experience needed for the job: 

• Experience validating availability, failover, and resilience characteristics (not just throughput/latency) 

• Experience assessing data integrity and consistency under concurrent load 

• Familiarity with Kubernetes and performance considerations in containerized environments (resource limits, scaling behavior, pod disruption) 

• Experience with event-driven / choreographed microservice patterns and messaging systems (e.g., NATS or similar) 

• Experience with MongoDB performance analysis (query profiling, indexing strategies, write concern trade-offs, replication lag) 

• Background in payments, fintech, or high-availability transaction processing where latency and throughput SLAs are critical 

• Familiarity with security testing or compliance validation practices 

• Experience producing customer-facing technical documentation (sizing guides, performance characterizations, capacity recommendations) 

Work Environment:  

• Standard Work Environment   

• Majority time spent on PC (Phys. Req.)  

• Travel required, may be domestic or international 

 
Applicants must be currently authorized to work in the United States on a full-time basis. This position does not offer sponsorship for employment visa status or work permit now or in the future. 

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 www.aciworldwide.com Job ID (Requisition #19158) 

ACI Worldwide is an AA/EEO employer in the United States, which includes providing equal opportunity for protected veterans and individuals with disabilities, and an EEO employer globally. 

Important Notice About Recruitment Scams 
Job seekers should be aware of ongoing recruitment scams where individuals or organizations impersonate legitimate companies to offer fake job opportunities. These scams often involve requests for personal information, payments, or interviews through unofficial channels. Please be cautious and verify any communications claiming to be from our company (www.aciworldwide.com / @aciworldwide.com). The ACI Worldwide recruitment team will always follow official channels and will never request payment. 

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