Senior Fullstack Software Developer (Backend Focused)

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Fullstack Software Developer (Backend Focused) based in Canada. This role offers the opportunity to build impactful software solutions that improve the way engineering teams develop, deliver, and maintain applications. You will work on a modern developer platform, solving complex technical challenges while creating scalable and reliable products. With a strong focus on backend development, you will collaborate closely with product, design, and engineering teams to deliver features that directly address customer needs. The position combines technical ownership, architectural decision-making, and opportunities to influence engineering practices. You will contribute to a remote-first environment that values collaboration, continuous learning, and high-quality craftsmanship. This is an ideal opportunity for an experienced engineer who enjoys building meaningful products and mentoring others. Accountabilities: Collaborate with product, UX, and engineering teams to understand customer challenges and develop effective software solutions. Design, build, test, and maintain high-quality backend-focused applications with a strong emphasis on reliability and scalability. Develop and maintain APIs, including GraphQL services that support user-facing applications and platform capabilities. Contribute to technical architecture decisions, improving system design, code quality, and long-term maintainability. Identify technical improvements, address technical debt, and promote best practices across engineering workflows. Lead technical explorations, create proof-of-concept prototypes, and evaluate solutions for complex engineering challenges. Execute projects effectively by communicating progress, identifying risks, and helping teams achieve development goals. Participate in operational responsibilities, including troubleshooting and improving systems across the technology stack. Mentor teammates and contribute to a culture of collaboration, knowledge sharing, and continuous improvement. Requirements: Strong experience building production web applications, with approximately 5+ years of experience with Ruby on Rails or 7+ years with comparable web frameworks such as Spring, Django, or Node.js. Solid understanding of backend architecture, API design, and software engineering best practices, including SOLID principles and clear separation of concerns. Experience designing performant data models and working extensively with relational databases, particularly MySQL. Strong knowledge of database optimization, indexing strategies, query performance, and data modeling decisions. Ability to write clean, maintainable, and well-tested code while maintaining a high standard of technical excellence. Collaborative and empathetic approach to problem-solving, with a pragmatic mindset focused on delivering valuable solutions. Comfortable learning new technologies quickly and adapting to evolving technical challenges. Experience working in cloud environments and modern infrastructure technologies is considered an asset. Familiarity with technologies such as AWS, Docker, Kubernetes, Terraform, Redis, Sidekiq, or similar tools is a plus. Experience scaling web applications for large user bases and high-volume workloads is an advantage. Benefits: Market-competitive compensation package based on experience, skills, and technical impact. Equity opportunities as part of the overall compensation package. Fully remote work environment with flexibility across Canada. Opportunity to work on a developer-focused platform used by innovative organizations. High level of ownership and autonomy in technical decision-making. Collaborative culture focused on growth, empathy, simplicity, and continuous improvement. Opportunities to mentor teammates and contribute to engineering excellence. Inclusive and welcoming workplace where employees are encouraged to bring their authentic selves to work. Supportive environment with accessibility accommodations throughout the hiring process. How Halcyon Labs works: We use an AI-powered matching process to ensure your application is reviewed quickly, objectively, and fairly against the role's core requirements. Our system identifies the top-fitting candidates, and this shortlist is then shared directly with the hiring company. The final decision and next steps (interviews, assessments) are managed by their internal team. We appreciate your interest and wish you the best! Why Apply Through Halcyon Labs? Data Privacy Notice: By submitting your application, you acknowledge that Halcyon Labs will process your personal data to evaluate your candidacy and share relevant information with the hiring employer. This processing is based on legitimate interest and pre-contractual measures under applicable data protection laws (including GDPR). You may exercise your rights (access, rectification, erasure, objection) at any time. #LI-CL1