Senior Software Engineer Backend​/Event-Driven Systems

Senior Software Engineer – Backend / Event-Driven Systems

Jacksonville, FL | Hybrid | Long-Term Contract (1+ Year)

ARC Group is seeking a Senior Software Engineer to join a small, highly specialized engineering team responsible for the technical integrity and continued development of a core backend platform. This is a hands-on engineering position for someone who enjoys building, securing, testing, and delivering production software—not an architecture-only, consulting, or oversight role.

The engineer will help build the operational backbone of a live, transaction-processing platform using event-driven and cloud-native technologies. The ideal candidate has deep experience designing and building event-driven systems, strong Python development skills, sound domain-modeling judgment, and a strong understanding of secure multi-tenant platforms. Our client is a Fortune 500 company near the Southside of Jacksonville, FL.

Key Responsibilities

• Design, develop, test, secure, and deliver high-quality backend software for a transaction-processing platform.
• Design and implement event-driven architectures using patterns such as Event Sourcing and CQRS.
• Develop domain models and determine when new business patterns require new solutions versus extensions of existing models.
• Build and maintain secure multi-tenant and multi-party systems with server-side tenant isolation and authorization.
• Ensure data and event integrity through appropriate authentication, authorization, signing, and encryption practices.
• Develop cloud-native, serverless solutions using object storage and serverless compute as primary building blocks.
• Develop relational database solutions, read models, and projections supporting transactional workloads.
• Build automated unit and integration testing and establish appropriate test coverage for critical functionality.
• Review and verify AI-generated code and test suites, identifying security vulnerabilities, authorization issues, edge cases, and inadequate test coverage.
• Own the quality bar and CI requirements for assigned development work.
• Work with containerized development environments and local cloud emulation for development and testing.
• Translate business and technical intent into precise specifications that can be implemented correctly.
• Take ownership of assigned deliverables from development through completion while maintaining quality and security standards.
• Communicate technical decisions, progress, risks, and trade-offs clearly to both technical and non-technical stakeholders.
• Work effectively within established architectural decisions and contribute in a direct, fast-moving team environment.

Required Qualifications

• 8+ years of hands-on software engineering experience with recent, personally developed and delivered production systems.
• Strong Python development experience.
• Proven experience designing and building event-driven architectures.
• Hands-on experience with Event Sourcing, CQRS, or comparable architectural patterns.
• Strong domain-modeling and backend architecture skills.
• Experience building secure multi-tenant or multi-party applications with server-side tenant isolation.
• Strong understanding of application and data security, including encryption in transit and at rest.
• Experience with relational databases and read-model/projection design.
• Experience developing automated unit and integration testing strategies.
• Experience with service mocking/stubbing, test-data generation, and CI quality gates.
• Experience with cloud-native/serverless development, including object storage and serverless compute.
• Container development and packaging experience.
• Experience with local cloud emulation or comparable development/testing environments.
• Strong understanding of software development lifecycle and production…