Sr. Software Engineer – Backend / API Engineering

Ontrac Solutions • Chicago, IL

2d • $110 - $120

About The Position

We are seeking a highly skilled and experienced Senior Software Engineer (Backend / API) to join a contractor program supporting a critical customer engagement: a state government professional licensing and regulatory compliance platform built on Google Cloud. This is greenfield work — infrastructure, data and CI/CD are in place, and the application services are still to be built. This role is ideal for a senior backend engineer with deep Java and Spring Boot experience who owns core domain services end to end and designs the APIs the rest of the platform is built on. The successful candidate will build the licensing, case management, payments, document and notification services and the public and internal API surface, working closely with the client technical lead, the integration engineers, and the mobile and frontend engineers to ensure project success from initial definition through final delivery.

Requirements

• 8+ years of professional backend engineering experience with Java and Spring Boot
• Production delivery experience on Google Cloud Platform
• Bachelor's degree in Computer Science or equivalent practical experience
• Java 21 and Spring Boot 3.x microservice development
• API design and ownership: REST, OpenAPI specification, versioning, pagination, error contracts, backward compatibility
• PostgreSQL, including schema design, indexing, query tuning, and versioned migrations
• GCP serverless services: Cloud Run, Pub/Sub, Cloud Tasks, Cloud Scheduler
• Event-driven architecture and messaging patterns (idempotency, retries, dead-letter handling)
• API security with OAuth 2.0 / OIDC and JWT, including role- and attribute-based authorization
• Automated testing (JUnit, integration tests) and CI/CD
• Observability of owned services: structured logging, metrics, tracing, SLOs

Nice To Haves

• Experience in government or regulated environments (FIPS, CJIS, HIPAA) — a plus, not a requirement
• Building APIs consumed by external partners, agencies, or public-facing applications
• AlloyDB, BigQuery
• Payment processing integrations and settlement reconciliation
• GraphQL or gRPC alongside REST
• Performance and load testing of high-traffic public services
• Google Cloud Professional certifications

Responsibilities

• Design and implement Java 21 / Spring Boot microservices on Cloud Run for the core domain: licensing, applications and renewals, case management, payments, documents, and notifications
• Own the platform API surface — specify it in OpenAPI, keep contracts stable for the mobile, frontend and integration teams, and version changes without breaking consumers
• Implement PostgreSQL (AlloyDB) persistence, including row-level data isolation, search indexing, and migration strategy
• Build asynchronous event flows on Pub/Sub and Eventarc, and publish the domain events other services and the integration layer subscribe to
• Implement scheduled and timer-driven processing with Cloud Tasks and Cloud Scheduler (renewal reminders, expiration sweeps, reconciliation)
• Implement authentication and authorization across the API surface, including public applicant access and internal staff roles
• Implement payment flows, including hosted payment page integration and settlement reconciliation
• Meet platform security and compliance requirements for encryption, auditability, and data isolation
• Deliver unit and integration test coverage, participate in code reviews, and support CI/CD deployment of owned services

What This Job Offers

• Job Type: Full-time
• Career Level: Senior