Saatchi & Saatchi

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, Buckley's, and Children's Advil, as well as several under the Mondelez banner (Crispers, Oreo, and Chips Ahoy 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 outstanding ideas into real tangible business results for the organization.

Overview Saatchi & Saatchi is seeking a

Lead Full Stack Developer

for an innovative AI platform initiative.

You have 8+ years building production software systems and at least a few years leading or anchoring a team technically. You are a hands‑on builder and you hold the architectural picture of a multi‑tier platform — React frontend, Spring Boot backend, FastAPI agentic services, agent SDKs on top of LLM providers. You are equally comfortable reviewing a database migration, debugging a prod incident, mentoring a senior engineer, or sitting in a client architecture conversation. You thrive at the intersection of architecture, engineering, and program reality.

Responsibilities

Own 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.

Pair closely with the Senior Technical PM and Program Director to translate product intent into a credible technical plan,



and to surface what is genuinely hard vs. what is just unfamiliar.

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

8+ years in software engineering, with meaningful time as a hands‑on lead, staff engineer, or solutions architect on production systems.

Proven experience designing and delivering complex, multi‑service platforms — not just one service or one tier.

Strong backend depth in at least one modern stack (Java/Spring Boot, Python/FastAPI, Node, Go, .NET); able to ramp on the others.

Solid frontend literacy — comfortable reading and reviewing modern React/TypeScript code and reasoning about state management, auth, and performance.

Strong cloud architecture background, preferably GCP (we run primarily on GKE); willing to deepen wherever the platform takes us.

Deep understanding of API design, integration patterns, distributed systems, and the failure modes that come with them.

Experience with containerization, Kubernetes, and modern CI/CD; you do not need to be a DevOps specialist, but you must operate well in that world.

Real production experience with AI / LLM systems — agents, RAG, evaluation, tool integration — or a strong, demonstrable plan for getting there.

Comfortable working within Agile delivery models (Scrum, Kanban, or whatever variant actually ships).

Excellent communication: you can explain a complex architecture to a non‑technical executive and disagree with a senior engineer respectfully and with evidence.

Required Soft Skills

Hands‑on bias — you reach for the code, the logs, and the diagram before you reach for the meeting invite.

Calm, decisive judgment when there is no ob

📌 Lead Full Stack Developer (Toronto)
🏢 Saatchi & Saatchi Canada
📍 Toronto