Sr Software Engineer

Job Summary

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 (Open Telemetry, Grafana) for correlating application metrics with test outcomes
• 5…