Senior Ruby on Rails Engineer

Sr. Ruby on Rails Engineer Summary We are seeking a Sr. Ruby on Rails Engineer to design, build, and maintain back-end systems that integrate with eCommerce and third-party platforms at scale. This role is heavily focused on asynchronous processing (background jobs, event-driven architecture, and message queues) and requires hands-on Shopify platform experience (custom apps, APIs, or Shopify Plus environments). The ideal candidate is comfortable owning integrations end-to-end, from data flow design through production monitoring. They need not be an expert but should understand options including AWS and SQS and be able to consult with others. Responsibilities Design, build, and maintain Ruby on Rails applications and services supporting core business and eCommerce workflows.Consult with clients to translate requests into Jira tickets, delegate work, and perform hands-on development.Develop and maintain asynchronous processing pipelines using background job frameworks (Sidekiq, Resque, or similar) and message queues (Kafka, RabbitMQ, SQS, or similar).Build and support integrations with Shopify (Admin API, storefront API, webhooks, or custom app development) and other third-party/eCommerce platforms.Architect event-driven systems that reliably synchronize data across internal services and external platforms.Write clean, tested, maintainable code and participate in code reviews.Troubleshoot and resolve issues in distributed systems including failed jobs, race conditions, and data consistency problems.Collaborate with Product, QA, and DevOps teams to ship features and improvements on schedule.Monitor system performance and reliability; implement improvements to scalability and fault tolerance.Document integration architecture, data flows, and API contracts for internal and client-facing reference.Requirements 5+ years of professional experience developing in Ruby on Rails and Node.js.eCommerce integration experience across PIMs, order management systems, payment providers, and multiple builds, along with the ability to make recommendations.Experience with Shopify extensions and functions, Ruby on Rails, Node.js, and PHP.Demonstrated experience with asynchronous/background processing (Sidekiq, Resque, Delayed Job, or similar) and message queue technologies.Hands-on experience with the Shopify platform including API integrations, custom app development, or Shopify Plus implementations.Solid understanding of RESTful and/or GraphQL API design and integration patterns.Experience with relational databases (PostgreSQL or MySQL) and query optimization.Working knowledge of event-driven architecture and webhook-based integrations.Familiarity with version control (Git) and CI/CD pipelines.Strong debugging skills across distributed, multi-service systems.Preferred Experience with Kafka, RabbitMQ, or AWS SQS/SNS in production environments.Familiarity with additional eCommerce platforms (BigCommerce, Magento, WooCommerce) beyond Shopify.Experience with containerization (Docker) and Cloud infrastructure (AWS, GCP, or Azure).Exposure to microservices architecture.Experience in a client-facing or consulting/staffing engagement environment; consultative approach, problem solver who is fluent in English with strong written and verbal communication skills, able to explain technical tradeoffs to non-technical stakeholders.Comfortable working independently and owning a system, end-to-end. This is a 12-month Contract opportunity with potential for hire with our Montreal, Quebec client. Low-cost employee benefits, paid time off and paid Holidays. H-1B visa sponsorship is not available for this position. No third-parties, please.