Senior Software Engineer - State Machines & Distributed

Humana Inc; Rockford (TN); On-site; USD 120,000 - 160,000; Full time

Job summary

Humana Inc. is seeking a Senior Software Engineer to design, implement, and operate stateful services that power real-time decisioning and personalization platforms. You will work with state machines, idempotency controls, and distributed systems to ensure correctness, resilience, and scalability.

The role emphasizes exactly-once processing, transactional state memory, and reliable outbox-based side effects. Strong expertise in concurrency and fault-tolerant design is required for this position.

Qualifications

• Experience designing and implementing state machines for lifecycle management.
• Understanding of idempotency and exactly-once processing.
• Experience with distributed systems and concurrency concepts.

Responsibilities

• Design, build, and maintain explicit state machines governing lifecycle transitions (e.g., open → in progress → completed → suppressed).
• Validate permissible transitions and support time-based and event-driven changes.
• Ensure state machines are clearly modeled, deterministic, auditable, and testable.
• Be robust against illegal or duplicate transitions through validation.
• Architect and manage transactional state stores as the single source of truth.
• Support safe, high-concurrency read/write operations and invariants across failures.
• Implement idempotency controls so requests can be retried and events processed once.
• Develop APIs and workflows resilient to retries, restarts, and replays.
• Use the outbox pattern to guarantee atomicity of state updates and event publication.
• Prevent loss or duplication of side effects and separate state mutation from downstream delivery.
• Enable replay, backfill, and recovery without breaching state guarantees.
• Integrate with messaging/streaming platforms for fault-tolerant delivery.
• Design for correctness under concurrency, partitions, failures, and redeployments.

Job description

Humana Inc. is seeking a Senior Software Engineer to design, implement, and operate stateful services that power real-time decisioning and personalization platforms. You will work with state machines, idempotency controls, and distributed systems to ensure correctness, resilience, and scalability.

The role emphasizes exactly-once processing, transactional state memory, and reliable outbox-based side effects. Strong expertise in concurrency and fault-tolerant design is required for this position.