ACI Worldwide is a global leader in mission- critical, real-time payments software. Our proven, secure and scalable software solutions enable leading corporations, fintechs and financial disruptors to process and manage digital payments, power omni-commerce payments, present and process bill payments, and manage fraud and risk. We combine our global footprint with a local presence to drive the real-time digital transformation of payments and commerce.

Senior Software Engineer

Engineering • Bangalore, India (Hybrid) • Full-Time

Mission-Critical Core Banking Platform • Cloud-Native • Low-Latency Transaction Processing

About the Role

ACI Worldwide is seeking a Senior Software Engineer to join the team building and operating a mission-critical, low-latency core banking platform. Our product is architected cloud-natively and containerized from the ground up, deployed initially on Microsoft Azure / AKS with a clear roadmap to Red Hat OpenShift, AWS, and Google Cloud Infrastructure (GCI). Every design decision — from threading models to deployment topology — is made with high throughput, sub-millisecond latency, and five-nines availability in mind.

This is a full-stack engineering role in the deepest sense: you will design and build features end to end, own the reliability and performance of what you ship, actively contribute to the CI/CD pipeline and quality strategy, and provide L3 production support when the platform counts on it. We are also on an active modernization journey, migrating mission-critical COBOL logic to modern Java services, and your ability to read, understand, and translate legacy COBOL will be highly valued.

We are looking for self-motivated, driven engineers who take pride in craftsmanship, embrace AI as an accelerator across the full development lifecycle, and are genuinely excited to grow their careers at ACI Worldwide.

Location & Work Model

Location: Bangalore , India

Work Model: Hybrid — on-site on designated days; remote-eligible on other days per team and business needs

Key Responsibilities

1) Low-Latency Application Engineering

• Design, implement, and optimize high-performance Java services for real-time transaction processing: payments, authorization, clearing, and settlement workflows where latency and correctness are non-negotiable.

• Apply deep JVM knowledge — threading models, garbage collection tuning, lock-free data structures, and async I/O — to sustain predictable throughput under peak load.

• Define and enforce performance budgets: author benchmarks, regression tests, and latency SLOs; profile and root-cause regressions before they reach production.

• Build against modern cloud-native patterns: microservices, event-driven messaging (NATS), reactive pipelines, and 12-factor application design.

2) Cloud-Native & Container-First Development

• Write software that is container-native from day one: images must be lean, stateless where possible, and fully operable on Kubernetes (AKS, OpenShift, EKS, GKE).

• Collaborate with the DevOps/Platform team on Kubernetes manifests, Helm/Carvel packaging, resource requests/limits, health probes, and rolling deployment strategies.

• Understand and contribute to GitOps workflows; ensure application configuration is version-controlled, auditable, and environment-agnostic.

• Design for multi-cloud portability from the start: avoid cloud-vendor lock-in in application code and dependency choices.

3) AI-Augmented Development Lifecycle

• Leverage AI tools actively across the SDLC: AI-assisted code generation and review, test case synthesis, documentation drafting, defect analysis, and performance diagnostics.

• Apply responsible AI practices: validate all AI-generated output for correctness, security, and maintainability before merging; never place secrets, PII, or PCI data into AI prompts.

• Contribute to team-level AI adoption: share effective patterns, prompt strategies, and tooling discoveries that raise the velocity and quality bar for the whole team.

• Stay current with AI/ML advancements relevant to banking — intelligent anomaly detection, automated triage, fraud signal enrichment — and propose production-ready applications.

4) Quality Engineering & Test Automation

• Own quality for what you ship: write comprehensive unit, integration, and contract tests; enforce non-negotiable coverage thresholds and quality gates in CI.

• Author and maintain end-to-end test scenarios for transaction processing flows; partner with Quality Engineering to integrate Testkube-orchestrated test suites into the pipeline.

• Practice shift-left quality: treat a bug escaping to staging as a process failure, not an expected outcome.

• Participate in code reviews with a quality lens: correctness, edge cases, error handling, observability hooks, and long-term maintainability.

5) Security & Compliance

• Write secure-by-design code in regulated financial environments: input validation, output encoding, least-privilege service identities, and safe secret consumption via ESO/vault integrations.

• Ensure compliance controls are built into the code — not bolted on afterward: PCI-DSS, SOC2, and audit logging requirements are first-class acceptance criteria.

• Participate in threat modeling sessions, security code reviews, and SAST/DAST remediation cycles; treat security findings with the same urgency as production incidents.

6) DevOps Collaboration & Engineering Excellence

• Engage actively with the DevOps/Platform team: contribute to pipeline definitions, own your service’s observability (structured logs, metrics, distributed traces), and participate in on-call rotations.

• Write and maintain runbooks, deployment guides, and architecture decision records (ADRs); documentation is a deliverable, not an afterthought.

• Champion engineering best practices: clean code, SOLID principles, API contract discipline, backward compatibility, and disciplined release management.

7) COBOL Modernization Support

• Read and interpret existing COBOL programs to extract business logic, data flow, and processing rules that must be faithfully reimplemented in modern Java services.

• Collaborate with domain experts and architects to validate that modernized Java implementations are behaviorally equivalent to legacy COBOL counterparts under all documented business scenarios.

• Document COBOL-to-Java translation decisions, edge cases, and business rule interpretations to build institutional knowledge for the long-term migration program.

8) L3 Production Support

• Serve as the third line of escalation for production issues on services you own: diagnose complex failures using logs, metrics, traces, and thread/heap dumps.

• Deliver timely, accurate root-cause analyses and post-incident reviews; implement durable fixes and preventive controls to eliminate recurrence.

• Maintain a “you build it, you run it” mindset: production reliability is a shared engineering accountability, not a handoff.

Required Qualifications

• 8+ years of professional software engineering experience; substantial time building production systems that handle high-volume, low-latency workloads.

• Java — expert-level proficiency: JVM internals, concurrency, performance tuning, Spring Boot / Spring ecosystem, and modern Java (17+) features.

• Low-latency systems — demonstrated experience designing and optimizing transaction processing, payments, or equivalent high-throughput distributed systems.

• Microservices & APIs — RESTful and event-driven service design; experience with API versioning, backward compatibility, and contract testing.

• Containers & Kubernetes — hands-on experience containerizing Java applications and running them on Kubernetes (AKS, EKS, GKE, or OpenShift).

• Cloud platforms — Azure (primary); working familiarity with AWS or GCI a strong plus.

• CI/CD & DevOps — experience with Jenkins, Gradle, container image builds, and automated quality gates; comfortable contributing to pipeline definitions.

• Test automation — strong unit, integration, and e2e testing discipline; experience with JUnit 5, Mockito, Testcontainers, or equivalent.

• Security — secure coding practices in regulated environments; familiarity with OWASP Top 10, input validation, and secrets management.

• Observability — structured logging, metrics (Micrometer/Prometheus), and distributed tracing (OpenTelemetry or equivalent).

• Databases — PostgreSQL (or equivalent relational DB) in production; familiarity with schema migration, query optimization, and connection pooling.

• AI-assisted development — active use of AI coding tools (Copilot, Claude, Cursor, or equivalent) with disciplined validation practices.

Preferred Qualifications

• Banking or payments domain experience : core banking, payment processing, ACH, SWIFT, card authorization, or clearing & settlement. Understanding of 8583 , 20022 specs and implementations based on it

• Drools / rule engine experience : authoring and maintaining business rules in Drools (KIE) or a comparable BRMS; ideally applied to transaction routing, risk, or eligibility logic.

• NATS messaging : operational experience building event-driven services on NATS or equivalent (Kafka, Pulsar, RabbitMQ).

• Multi-cloud portability : experience deploying identical workloads across two or more of Azure, OpenShift, AWS, and GCI.

• COBOL literacy — ability to read and interpret COBOL programs sufficiently to extract and translate business logic into Java.

• Carvel toolchain : familiarity with ytt, kapp-controller, or imgpkg for Kubernetes-native packaging and GitOps.

• Regulated environment experience : PCI-DSS, SOC2, GDPR, or equivalent compliance frameworks embedded in engineering practices.

• AI/ML feature delivery : experience shipping AI or ML capabilities as part of a production product (anomaly detection, intelligent routing, fraud signals, etc.).

• Technical mentorship : demonstrated experience upleveling junior engineers through code review, pair programming, or structured coaching.

What We Offer

• Technically challenging work on a platform that processes mission-critical banking transactions for global financial institutions.

• A cloud-native, automation-first engineering culture that invests in quality, security, and developer experience as competitive advantages.

• Real career growth: ACI actively develops engineers into senior technical leaders and engineering managers; your trajectory here is yours to define.

• An AI-forward team that embraces modern tooling and gives engineers the latitude to experiment, improve, and lead.

• Competitive compensation and benefits package; hybrid flexibility

LI-AP

ACI Worldwide is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, national origin, disability, or veteran status.