Senior Software Engineer - NBA

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

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We are seeking an accomplished Senior Software Engineer to design, implement, and operate mission-critical stateful services that form the backbone of real-time, automated decisioning and personalization platforms. These systems are responsible for maintaining authoritative state, orchestrating lifecycle transitions, and ensuring reliable downstream effects—often in high-concurrency, low-latency environments.

This position is ideal for engineers with a strong grasp of state machines, idempotency, distributed systems, and “exactly-once” execution semantics. You will also employ advanced AI-assisted and agentic engineering tools to drive correctness, velocity, resilience, and scalability.

Key Responsibilities

State Machine Architecture & Implementation

• 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

Transactional State Memory & Exactly-Once Processing

• 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

Reliable Side Effects via Outbox Pattern

• 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

Distributed Systems & Concurrency Management

• Design for correctness under concurrent updates, network partitions, partial failures, and service redeployments
• Apply expertise in: