Senior Software Engineer - NBA

Humana is a U.S. healthcare company providing insurance and healthcare services. The Senior Software Engineer will design, implement, and operate mission-critical stateful services for real-time automated decisioning and personalization platforms, with a focus on state machines, transactional state management, exactly-once processing, distributed systems, observability, and AI-assisted engineering. The role also involves collaboration, architecture reviews, and mentoring engineers.

Responsibilities:

• Design, build, and maintain explicit state machines governing: Lifecycle transitions (e.g., open → in progress → completed → suppressed); Validation of permissible transitions; Time-based and event-driven changes
• Ensure state machines are: Clearly modeled and not hidden in code logic; Deterministic, reproducible, and auditable; Easily understood and testable; Robust against illegal or duplicate transitions through comprehensive validation
• Architect and manage transactional state stores serving as the single source of truth
• Support safe, high-concurrency read/write operations
• Uphold system invariants across partial failures and recovery scenarios
• Implement robust idempotency controls so: Requests can be safely retried; Commands execute at most once; Duplicate events do not compromise state integrity
• Develop APIs and workflows resilient to retries, restarts, and replay events
• Employ the outbox pattern to guarantee atomicity of state updates and event publication
• Prevent loss or duplication of side effects
• Maintain clear separation between state mutation and downstream event delivery
• Facilitate replay, backfill, and recovery operations without breaching state guarantees
• Integrate seamlessly with messaging and streaming platforms, ensuring fault tolerance
• Design for correctness under concurrent updates, network partitions, partial failures, and service redeployments
• Apply expertise in: Idempotency keys; Optimistic and pessimistic locking strategies; Event ordering and causality
• Balance rigorous correctness with performance and latency requirements
• Leverage AI-powered and agentic tools to: Automatically generate and validate state transition tests; Probe edge cases and concurrency challenges; Assist in code reviews, refactoring, and documentation; Accelerate debugging, incident analysis, and root cause discovery
• Use AI responsibly to enhance productivity while maintaining clarity and system integrity
• Engineer services with robust observability through: Structured logging, metrics, and alerting; Distributed tracing
• Ensure all state transitions and emitted events are: Fully traceable and reproducible; Auditable for compliance and investigative needs
• Partner with platform, data, and quality engineering teams to assure end-to-end reliability
• Participate in architecture and design reviews to elevate system quality standards
• Mentor and guide engineers on best practices for safe, reliable, and maintainable distributed systems

Requirements:

• • Bachelor's degree in computer science or related field
• • 6+ years of experience in backend or platform engineering
• • Demonstrated hands-on expertise with:
• • State machine modeling and lifecycle management
• • Transactional state stores
• • Idempotent API and workflow design
• • In-depth understanding of:
• • Exactly-once or effectively once processing
• • Failure modes in distributed environments
• • Proficiency in one or more contemporary languages (e.g., Java, Kotlin, Go, Python)
• • Experience with AI-assisted development tools for productivity and code quality
• Qualified candidates are required to currently live in, or be willing to move to, a commutable distance for a hybrid (~3 days in-office) work arrangement
• • Washington, D.C. metropolitan area
• • Louisville, KY metropolitan area
• • Denver, CO metropolitan area
• • Dallas, TX metropolitan area
• • Ft. Lauderdale, FL metropolitan area
• Occasional travel to Humana's offices for training or meetings may be required
• Very minimal travel might be required for training, meetings, and/or conferences
• • Experience with outbox, transactional messaging, or event sourcing patterns
• • Familiarity with low-latency, high-throughput architectures
• • Operational experience in systems requiring strict auditability and correctness
• • Background in regulated or mission-critical domains