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
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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.
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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.
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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.
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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).
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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.
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Mentor mid-level and senior engineers; coach them through technical decisions, on-call experiences, and difficult code reviews.
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Partner with the Platform Engineer on production reliability — capacity, scaling, observability, and incident response — and own application-side reliability concerns.
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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.
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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.
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Build redundancy on yourself — pair, document, rotate ownership, and ensure no critical system has exactly one person who understands it.
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8+ years in software engineering, with meaningful time as a hands-on lead, staff engineer, or solutions architect on production systems.
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Proven experience designing and delivering complex, multi-service platforms — not just one service or one tier.
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Strong backend depth in at least one modern stack (Java/Spring Boot, Python/FastAPI, Node, Go, .NET); able to ramp on the others.
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Solid frontend literacy — comfortable reading and reviewing modern React/TypeScript code and reasoning about state management, auth, and performance.
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Strong cloud architecture background, preferably GCP (we run primarily on GKE); willing to deepen wherever the platform takes us.
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Deep understanding of API design, integration patterns, distributed systems, and the failure modes that come with them.
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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.
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Real production experience with AI / LLM systems — agents, RAG, evaluation, tool integration — or a strong, demonstrable plan for getting there.
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Comfortable working within Agile delivery models (Scrum, Kanban, or whatever variant actually ships).
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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
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Hands-on bias — you reach for the code, the logs, and the diagram before you reach for the meeting invite.
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Calm, decisive judgment when there is no obviously right answer.
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Strong written communication — you can write a one-page architecture rationale that future-you will still understand.
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Generous mentorship instinct — you make the people around you better, on purpose.
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Comfortable with ambiguity and willing to make reversible decisions quickly while flagging the irreversible ones for broader input.
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Pragmatic about technology choices — you optimize for the team's ability to operate the system, not for personal stack preferences.
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Honest about what you do and do not know; willing to say 'I'll find out' and then actually find out.
Nice to Have
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Prior experience working inside Publicis Groupe or another large holding-company agency network.
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Production experience with Google ADK, LangGraph, LlamaIndex, or comparable agent frameworks.
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Experience with event-driven architectures, domain-driven design, and contract-first integration patterns.
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Background in regulated or privacy-sensitive environments (identity, healthcare, financial, marketing-compliance).
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Experience supporting multiple products or clients on a shared platform (multi-tenant, multi-brand, white-label).
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Comfort with Terraform, Kustomize, or other IaC tooling at a 'can read and improve' level.
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Track record contributing to internal developer experience — patterns, scaffolds, golden paths.
