Our client is currently seeking a Sr Ruby on Rails Engineer

We are seeking a Senior Rails Engineer to help lead both the modernization of our current B2B/B2C eCommerce platform and the evolution of how our engineering organization builds software.

Our core application is undergoing a strategic platform modernization: systematically retiring legacy PHP services into a modern, Rails-centered architecture using the Strangler Fig pattern. At the same time, we are actively building an AI-enabled software factory—changing how our team turns business intent into safe, maintainable, production-ready software.

In this role, AI acts as a key accelerator for research, generation, and execution, but core engineering judgment, architectural integrity, and production safety remain fully human responsibilities. Leadership here is demonstrated through end-to-end ownership, technical influence, mentoring, and rigorous judgment.

Key Responsibilities

1. Platform Modernization (40%)

• Strangler Fig Execution: Lead the incremental, reversible retirement of legacy PHP capabilities into Ruby on Rails without relying on high-risk, "big-bang" migrations.

• End-to-End Capability Ownership: Trace legacy capabilities across all touchpoints—server-rendered or React UIs, API boundaries, business logic, persistence layers, background queues, permissions, and operational dependencies.

• Behavior Preservation: Maintain strict parity with existing systems during migrations, ensuring any deliberate behavior changes are identified, approved, and thoroughly tested.

• Legacy Cleanup: Ensure full migration completion by safely removing obsolete entry points, feature flags, dead code, and temporary bridges after Rails becomes authoritative.

2. Software Factory & AI Engineering (30%)

• Agentic Workflow Leadership: Direct specialized AI developer agents across discovery, implementation, testing, documentation, and QA handoffs.

• Adversarial Review: Critically evaluate AI-generated code for semantic parity gaps, missed edge cases, security risks, performance bottlenecks, and weak test coverage.

• Factory Optimization: Help design and refine our AI workflows—defining clear agent roles, acceptance criteria, automated guardrails, evidence capture, and QA controls.

• Standardization: Turn lessons learned, QA findings, and edge-case corrections into reusable prompt architectures, automated linters, and team engineering standards.

3. eCommerce Product & Platform Development (20%)

• Core Commerce Features: Design and implement capabilities across complex domain areas, including product catalogs, search, dynamic pricing, quoting, order processing, and ERP integrations.

• Extension & Plugin Architecture: Contribute to a governed plugin/extension architecture that allows internal and external teams to build extensions safely without compromising the core platform.

• Domain Discovery: Collaborate directly with product managers and business stakeholders to uncover hidden domain rules, resolve ambiguity, and translate business needs into testable requirements.

4. Engineering Excellence (10%)

• Operational Safety: Improve shared CI/CD pipelines, automated testing, deployment safety controls, feature flagging, and production observability.

• Agile Execution: Actively participate in 1-week Scrum sprints (planning, standups, reviews, and retrospectives).

• Behavioral Testing: Write tests focused on observable behavior and real business contracts rather than internal implementation details.

What We’re Looking For

Required Qualifications & Skills

• Ruby on Rails Expertise: Deep, production-scale experience building, debugging, refactoring, and scaling Rails applications.

• Legacy Modernization Experience: Proven track record of incrementally replacing legacy codebases or monoliths while maintaining continuous delivery.

• eCommerce / Complex Domain Depth: Experience handling complex transaction flows, product catalogs, pricing/tax rules, inventory management, or enterprise integrations.

• Full-Stack Ownership: Ability to own a feature end-to-end—from frontend rendering and API contracts to Rails logic, database queries, background jobs, and operational deployment.

• Data & Systems Architecture: Strong relational database design skills (PostgreSQL/MySQL), state machine management, caching, message queues, and async background processing.

• AI Tooling & Critical Evaluation: Practical experience directing AI coding agents, with a clear ability to spot confidently wrong outputs, hallucinated logic, or unsafe state changes.

• Pragmatic Testing & Safety: Strong focus on automated testing, feature flags, canary rollouts, and rollback readiness.

Preferred Qualifications

• Experience integrating Rails applications with enterprise ERP systems (e.g., NetSuite, SAP, or similar).

• Modern frontend development experience with React.

• Deep understanding of B2B/B2C commerce flows (e.g., custom price books, tiered quoting, complex shipping/tax workflows).

• Familiarity with structured AI agent frameworks or orchestration workflows (e.g., LangGraph, CrewAI, AutoGen, or custom agent systems).

• Experience designing multi-tenant or governed plugin architectures.

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