Principal Full Stack Developer (AI Product)

Company description Saatchi & Saatchi is part of Publicis Group Canada and is an advertising agency with the belief that creativity, data, media and technology should all work together, and we use that to influence human behavior and drive success for clients. S&S is one of the world's largest agency networks with 114 offices and more than 6000 employees globally. Here in our Toronto office we work with some of the countries most valued brands including Toyota, Lexus, Quesada and Mondelez just to name a few. We’re an award winning agency in both creativity and effectiveness, so it’s really important for us here to convert that innovation and the great ideas into real tangible business results for the organization. Overview Saatchi & Saatchi Canada is excited to announce a new opening for a Principal Full Stack Developer to join an innovative, forward-thinking AI initiative. This role will begin as a 12-month contract, with the possibility of conversion to a permanent position in 2027, depending on performance and budget allocation. This is an exciting opportunity to help shape the technical direction and architecture of an ambitious enterprise AI solution while remaining hands-on in its development. You’ll tackle complex engineering challenges, build scalable, production-ready AI capabilities, and mentor other developers in a fast-paced, highly collaborative environment focused on delivering meaningful business impact. You’ll work closely with the leadership and design teams to create thoughtful, intuitive user experiences, while collaborating alongside AI experts to turn advanced AI capabilities into scalable, user-focused solutions. Together, you’ll bridge design, engineering, and AI to bring complex ideas to life and deliver meaningful value to users and clients. Responsibilities Participate in shaping the technical direction across the platform's tiers — frontend, backend, agentic/AI services, data, and integrations — and hold the shared mental model of how the system actually fits together. Lead architecture and design reviews, write the deciding ADR when needed, and keep a small set of vendor-neutral patterns the team can lean on instead of a sprawl of frameworks. Stay hands-on in the code — pick up meaningful slices of work, especially across tier boundaries (e.g. backend ↔ agentic, frontend ↔ auth/RBAC, infra-aware app changes). Be a first-class code reviewer across the stack: you set the bar for clarity, testability, security, and operability, and you raise the team's bar by reviewing thoughtfully. Mentor mid-level and senior engineers; coach them through technical decisions, on-call experiences, and difficult code reviews. Partner with the Platform Engineer on production reliability — capacity, scaling, observability, and incident response — and own application-side reliability concerns. Drive integration architecture with internal and external systems using API-first and event-driven patterns; ensure identity, authorization, data protection, and auditability are built in, not bolted on. Champion the LLM/agent layer — agent orchestration, tool/plugin design, prompt and evaluation loops, provider abstraction (e.g. Vertex AI, Claude on Vertex, OpenAI) — and keep us out of vendor lock-in we cannot pay for. Build redundancy on yourself — pair, document, rotate ownership, and ensure no critical system has exactly one person who understands it. Qualifications 12+ years of professional experience building end-to-end solutions, including technical leadership and ownership of complex systems. Proven experience mentoring developers, providing technical guidance, and raising engineering standards across the team. Demonstrated ability to deliver high-quality solutions in fast-paced, evolving environments. Experience building AI-powered features or integrating AI capabilities into production solutions is strongly preferred. Strong proficiency in Java (Spring Boot, Spring Framework) for backend development. Hands-on experience with React, TypeScript, and modern JavaScript frameworks. Experience with cloud platforms, particularly Amazon Web Services (AWS) and Google Cloud Platform (GCP), with a willingness to deepen expertise. Solid understanding of RESTful API design and microservices architecture. Experience with containerization (Docker) and familiarity with container orchestration concepts. Familiarity with SQL and NoSQL databases (PostgreSQL, MongoDB, or similar). Understanding of web accessibility standards (WCAG 2.1) and inclusive design principles. Experience with Git version control and collaborative development workflows. Knowledge of CI/CD practices and tools. Additional information Location & Eligibility: Candidates must be based in Canada, with valid Canadian work authorization of at least 12 months. Remote Work: This role is remote. If you are GTA-based, the team meets once a month at our Toronto office (111 Queen St. E, Suite 200, Toronto, ON M5C 1S2). Time Off: Up to 3 weeks vacation, with additional paid closure between Christmas and New Year's Extended long weekends for provincial holidays — we give you both the Monday and Friday so you get a full 4-day break 10 personal days per year Flexibility & Global Mobility: After completing one year, work remotely for up to 6 weeks per year from any of our 50+ global offices through our Work Your World program. Benefits: Comprehensive group coverage including: Medical, dental, and vision care Psychological and paramedical services Disability insurance Fertility support and gender-affirming care Dedicated internal guidance programs for employees navigating cancer, fertility treatments, or gender transition Gym Membership: Corporate Membership rates at Good Life Fitness Free access to a financial planner & more… Compensation: The salary range for this position is $145,000–$175,000 per year, based on experience, skills, and relevant certifications. We believe in pay transparency and are committed to offering competitive, market-aligned compensation. We use artificial intelligence (AI) tools to support parts of our hiring process, such as reviewing applications or analyzing resumes. These tools assist our recruitment team but never replace human decision-making. We believe in a human-first approach, where your experience and potential are recognized by people. Saatchi & Saatchi is committed to building a diverse workforce representative of our community. We encourage and are pleased to consider all qualified candidates, without regard to race, colour, citizenship, religion, sex, marital / family status, sexual orientation, gender identity, aboriginal status, age, disability or persons who may require an accommodation, to apply. If you require a specific accommodation please contact Human Resources at or by email at .
Participate in shaping the technical direction across the platform's tiers — frontend, backend, agentic/AI services, data, and integrations — and hold the shared mental model of how the system actually fits together. Lead architecture and design reviews, write the deciding ADR when needed, and keep a small set of vendor-neutral patterns the team can lean on instead of a sprawl of frameworks. Stay hands-on in the code — pick up meaningful slices of work, especially across tier boundaries (e.g. backend ↔ agentic, frontend ↔ auth/RBAC, infra-aware app changes). Be a first-class code reviewer across the stack: you set the bar for clarity, testability, security, and operability, and you raise the team's bar by reviewing thoughtfully. Mentor mid-level and senior engineers; coach them through technical decisions, on-call experiences, and difficult code reviews. Partner with the Platform Engineer on production reliability — capacity, scaling, observability, and incident response — and own application-side reliability concerns. Drive integration architecture with internal and external systems using API-first and event-driven patterns; ensure identity, authorization, data protection, and auditability are built in, not bolted on. Champion the LLM/agent layer — agent orchestration, tool/plugin design, prompt and evaluation loops, provider abstraction (e.g. Vertex AI, Claude on Vertex, OpenAI) — and keep us out of vendor lock-in we cannot pay for. Build redundancy on yourself — pair, document, rotate ownership, and ensure no critical system has exactly one person who understands it.
12+ years of professional experience building end-to-end solutions, including technical leadership and ownership of complex systems. Proven experience mentoring developers, providing technical guidance, and raising engineering standards across the team. Demonstrated ability to deliver high-quality solutions in fast-paced, evolving environments. Experience building AI-powered features or integrating AI capabilities into production solutions is strongly preferred. Strong proficiency in Java (Spring Boot, Spring Framework) for backend development. Hands-on experience with React, TypeScript, and modern JavaScript frameworks. Experience with cloud platforms, particularly Amazon Web Services (AWS) and Google Cloud Platform (GCP), with a willingness to deepen expertise. Solid understanding of RESTful API design and microservices architecture. Experience with containerization (Docker) and familiarity with container orchestration concepts. Familiarity with SQL and NoSQL databases (PostgreSQL, MongoDB, or similar). Understanding of web accessibility standards (WCAG 2.1) and inclusive design principles. Experience with Git version control and collaborative development workflows. Knowledge of CI/CD practices and tools.