Lead Full Stack Engineer

Atos SE; Greater London; Hybrid; GBP 90,000 - 120,000; Full time

Job summary

Atos is seeking a Lead Full Stack Engineer to shape secure, AI-enabled, production-grade software for government and enterprise clients. You will write production code, own delivery, and set engineering standards while remaining hands-on.

Eligibility to obtain SC clearance is required or can be demonstrated quickly; you will mentor teams, design complex systems, and influence technical strategy across frontend, backend, APIs, and cloud platforms.

Qualifications

• Proven hands-on software engineering experience across frontend, backend and integrations.
• Strong system-design capabilities with end-to-end ownership.
• Experience delivering AI-enabled production systems in regulated environments.

Responsibilities

• Lead design and delivery of secure, resilient applications.
• Remain hands-on across frontend, backend, APIs, data, and cloud.
• Build and evaluate AI-enabled workflows and agentic capabilities.
• Set engineering standards and best practices for multiple teams.
• Mentor engineers and guide teams through complex delivery.
• Collaborate with clients, architects and product leaders to ensure outcomes.

Skills

Hands-on engineering

System design

AI-enabled software

SC clearance eligibility

APIs

Cloud platforms

CI/CD

Security

Mentoring

Government/regulated experience

Tools

CI/CD

Docker

Kubernetes

Cloud platforms

RAG

Job description

Select how often (in days) to receive an alert:

Atos is the Atos Group brand dedicated to AI-powered, secure, end-to-end digital services. Atos designs, develops, and operates critical digital environments that drive performance, resilience and sovereignty, helping public and private organizations worldwide retain control over their data and infrastructures, while meeting regulatory requirements.

With more than 52,000 employees serving over 4,500 clients across 54 countries, Atos helps modernize core IT systems, accelerate cloud and data transformation, strengthen cybersecurity, and deliver secure digital workplace environments to support its clients, its employees and society. Atos also provides consulting and advisory services through its Atos Amplify brand.
A trusted partner in operating complex and mission‑critical environments, Atos supports organizations across highly regulated and sovereign contexts.

Atos Group is a global leader in digital transformation with c. 54,000 employees and annual revenue of c. €7.2 billion, operating in 54 countries under two brands - Atos for services and Eviden for products and systems. European number one in cybersecurity and a leader in cloud, Atos Group is committed to a secure and decarbonized future and provides tailored AI-powered, end-to-end solutions for all industries. Atos Group is listed on Euronext Paris.

About Our Team

Our Full stack engineering team brings together experienced engineers, diverse perspectives, and a flat team structure that enables visibility and impact from day one. With 40–50 professionals across the practice, we deliver some of the most exciting projects in the market — from next‑generation fintech payment platforms to global insurance systems deployed across multiple countries.

AI is an important part of our work, but this role is grounded in strong software engineering fundamentals. We are looking for senior engineers who enjoy architecture, system design, and end‑to‑end delivery, with a genuine interest in modern technologies, including AI.

The role requires Security Clearance or ability to get SC in short timescales

We are looking for an exceptional Lead Full Stack Engineer who wants to solve difficult problems, build important systems and remain genuinely hands‑on.

You will lead the engineering of complex, high‑profile software and AI‑enabled solutions for major government and enterprise clients. These are environments where security, resilience, scale and sound technical judgement matter, and where the systems you build deliver real operational outcomes.
This is not a coordination role or an architecture position detached from delivery. You will write production code, tackle the hardest technical challenges, make critical design decisions and set the engineering standard for the teams around you.

What exceptional looks like

You can enter an unfamiliar programme, understand the system quickly, identify the real constraints and establish a credible technical route forward.
You can design the solution, build its most difficult components, integrate models and tools, implement the necessary controls and explain your decisions to a senior client. You make good engineers better and leave behind stronger systems, practices and teams.
You combine the depth of a principal engineer, the breadth of a full stack engineer, the practical capability of an AI engineer and the judgement of a trusted technical consultant.
If you still love building software, want ownership of genuinely difficult engineering challenges and care about delivering systems that work in the real world, we would like to hear from you.

What makes this role different

You will have the opportunity to:

• Shape technically ambitious programmes from discovery through to production.
• Work across modern software engineering, cloud, AI and agentic AI.
• Solve complex problems without being constrained to a single technology stack.
• Test new technologies and approaches against real delivery challenges.
• Influence engineering standards, reusable patterns and technical strategy.
• Work directly with senior client stakeholders and become a trusted technical adviser.
• Mentor strong engineers and build high‑performing engineering teams.
• Deliver systems with meaningful impact across major government and enterprise services.

What you’ll do

• Lead the design and delivery of secure, resilient and production‑grade applications.
• Remain hands‑on across frontend, backend, APIs, data, integration, cloud and deployment.
• Build AI‑enabled applications and agentic workflows that connect models, tools, data and enterprise systems.
• Design agent orchestration, retrieval, context, state, memory, permissions and human oversight.
• Establish robust approaches to AI evaluation, security, reliability, observability and cost.
• Solve difficult problems across architecture, performance, scalability and production operations.
• Make pragmatic technical decisions based on evidence and clearly explain the trade‑offs.
• Lead teams through ambiguity and complex delivery rather than waiting for perfect requirements.
• Raise engineering standards through practical leadership, mentoring and constructive challenge.
• Work closely with clients, architects, product teams and delivery leaders.

What we’re looking for

You will be an outstanding software engineer who has developed into a technical leader without moving away from engineering.

You will bring:

• Exceptional and recent hands‑on software engineering experience.
• A record of personally delivering complex, production‑grade systems.
• Deep understanding of how modern systems operate end to end.
• Strong system‑design and architecture capability backed by the ability to implement and validate your decisions.
• Broad experience across frontend, backend, APIs, databases, automated testing, CI/CD, containers and cloud platforms.
• Experience diagnosing difficult issues across application, infrastructure and runtime boundaries.
• Genuine technology independence and the ability to master unfamiliar tools and platforms quickly.
• Strong judgement across security, performance, reliability, maintainability, observability and cost.
• Experience leading and mentoring excellent engineers while remaining technically credible.
• The confidence to challenge weak assumptions and defend better technical approaches.
• Excellent communication and client‑facing skills.
• Experience working in government, regulated or complex enterprise environments.
• Eligibility and willingness to obtain SC clearance.

AI and agentic AI capability

You will have practical experience taking AI beyond demonstrations and into secure, supportable production environments.
We are looking for experience in areas such as:

• Building applications using large language models or other modern AI models.
• Designing agentic workflows involving tool use, structured outputs and external system integration.
• Retrieval‑augmented generation, embeddings, grounding and context management.
• Agent orchestration, state, memory, permissions, error recovery and human‑in‑the‑loop controls.
• Evaluation of quality, reliability, safety and measurable business outcomes.
• AI security, including prompt injection, data protection, access control and auditability.
• Hosted, private, open‑weight, sovereign or disconnected deployment patterns.
• AI‑assisted software engineering, with rigorous validation of generated code and designs.

Just as importantly, you will know when AI is the right solution and when conventional deterministic software is the better engineering choice.

Diversity, Equity & Inclusion

Here at Atos, diversity and inclusion are embedded in our DNA. Read more about our commitment to a fair work environment for all. As a Disability Confident employer, we encourage applications from all applicants, especially, differently abled applicants. We aim to ensure that those who meet the minimum criteria for this position will be offered an interview. We are committed and willing to making reasonable adjustments to the application and assessment process to accommodate your needs.

Here at Atos, diversity and inclusion are embedded in our DNA. Read more about our commitment to a fair work environment for all.

Atos is a recognized leader in its industry across Environment, Social and Governance (ESG) criteria. Find out more on our CSR commitment.