Sr Java Back End Engineer
Senior Java Backend Engineer
Location: Hybrid (Chicago, New York, Boston, Dallas)
Contract Type: Freelance mission with clear path to Contract-to-Hire
Team: Approximately 10 engineers, Scrum methodology
About the Role
We are rebuilding a mission-critical trading and risk platform from the ground up. You will design, implement, and optimize backend services that power real-time trading and reporting. This role focuses on microservices architecture, secure API design, and high-performance systems.
Responsibilities
- Architect and deliver microservices by decomposing a legacy monolith into Spring Boot services using Hexagonal Architecture principles.
- Implement JWT-based authentication and authorization for public REST APIs to ensure a secure gateway.
- Modernize reporting by migrating a legacy reporting module into scalable reporting microservices with guaranteed SLAs and clean data pipelines.
- Build new backend services for an exchange-grade trading platform, integrating FIX protocol and ensuring deterministic behavior under load.
- Drive TDD-first development, enforce clean code practices, and mentor peers on testing strategies.
- Profile and tune services for low latency, high throughput, and efficient concurrency.
Tech Stack You'll Own
- Core: Java SE/EE, Spring Boot, JMS, JDBC
- Testing: JUnit, Mockito, AssertJ, Hamcrest, Cucumber
- Build and CI/CD: Maven or Gradle, Jenkins, Git
- Data Layer: Oracle DB with MongoDB or Postgres for certain services
- Messaging and Protocols: FIX, Kafka (nice to have)
- Containerization and Orchestration: Docker, Kubernetes
- Tools: IntelliJ IDEA, Jira
Required Experience
- Senior-level Java expertise with proven delivery in finance or trading systems.
- Hands-on experience migrating monoliths to microservices including domain slicing, interface contracts, and observability.
- Strong grasp of security fundamentals such as JWT, token lifecycle, and API hardening.
- Deep knowledge of multithreading and concurrency, performance tuning, and memory optimization.
- Comfortable with CI/CD pipelines, containerization, and orchestration in production environments.
- Familiarity with FIX protocol, market data flows, or risk computation is a plus.
Nice-to-Haves
- Experience with Hexagonal Architecture and event-driven patterns.
- Oracle DB optimization including partitioning and query tuning.
- Exposure to Python or Bash for tooling or data preparation.
- Observability stack such as OpenTelemetry, Prometheus, or Grafana.
Engagement Model
- Start as a freelance contractor (Corp-to-Corp or W2 via partner).
- Clear milestones tied to conversion with a contract-to-hire path once modernization streams hit agreed outcomes.
FAQs
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