Who we are

The role 

Collaborating closely with our dynamic team of product designers and engineers, you will play a pivotal role in shaping the foundation of frontend at Helsing. Embracing a hands-on approach, you'll not only lead by example, but also spearhead the development and expansion of a tight-knit team that works across a wide-range of internal teams and products. Your primary emphasis will be on enhancing usability, creating re-usable foundations for multiple front-ends and optimising the end-user experience across the entire company.

The day-to-day

• Review code contributions, proposals, and RFCs from colleagues. At Helsing we strongly believe that unblocking others takes precedence over spending more time on your own work.

• Own the user interface end-to-end, from early wireframes and prototypes through to performant, production-ready code. You'll work closely with product and UX colleagues to shape how users interact with our tools. We have relatively few frontend engineers at Helsing; this means that we operate at a high level of autonomy and there are plenty of opportunities for impactful work.

• Propose and implement new features, capabilities, tooling, visualizations, or even full products across our stack. We encourage our engineers to look beyond their immediate team for missed opportunities, and to speak up when they identify one.

• Establish and evolve our React component library, ensuring consistency, reusability, and alignment with our visual design standards across multiple front-ends.

• Collaborate with others beyond your team and share knowledge with the wider frontend community at Helsing. Contribute to establishing our frontend engineering standards. Build or adopt tools that help enforce these standards, or make our frontend engineers more efficient in a different way.

• Become a mentor, find a mentee, and help support and develop our interviewing pipeline. The people make or break the company, and we want as many engineers as possible to be part of fostering and growing the organisation.

• Share your experience and technical know-how with other Helsingers. We host tech talks, get together for smaller "let's learn together" groups, run topical office hours or reading groups (e.g., on React or TypeScript), etc. to help each other get better with time.

• Connect with, understand, and make changes to backend systems as needed. Our backends are primarily written in Rust, and you'll need to be comfortable navigating unfamiliar codebases to unblock yourself and improve integrations. Rust experience is not a prerequisite to this role, though - you can learn that over time as needed.

• Present your work at our weekly demo sessions. We want engineers to come together around what they are working on and to feel like they are not endlessly squirrelling away at something that doesn't matter. To that end, we host (and actively work towards) demo sessions that allow early feedback, celebration of progress, and a better shared understanding of everything that goes on at Helsing.

You should apply if you

• Can write legible, maintainable, and performant frontend code - ideally using TypeScript and React.

• Are experienced with APIs and server-client communication like REST and GraphQL.

• Have experience with running a live production software.

• Are passionate about staying on top of current development best practices, libraries and frameworks.

• Are comfortable working with unfamiliar backends, ideally with some exposure to languages like Rust.

• Communicate well in English, both verbally and in writing.

• Enjoy collaborating with others, including reviewing code and pair programming.

• Are comfortable working asynchronously (writing PRs and RFCs, having discussions by email).

• Strive to improve yourself, your peers, and the culture you work in over time.

• Feel like ethical considerations are an inherent part of engineering.

Note: We operate at an intersection where women, as well as other minority groups, are systematically under-represented. We encourage you to apply even if you don’t meet all the listed qualifications; ability and impact cannot be summarised in a few bullet points.

Join Helsing and work with world-leading experts in their fields 

• Helsing’s work is important. You’ll be directly contributing to the protection of democratic countries while balancing both ethical and geopolitical concerns

• The work is unique. We operate in a domain that has highly unusual technical requirements and constraints, and where robustness, safety, and ethical considerations are vital. You will face unique Engineering and AI challenges that make a meaningful impact in the world

• Our work frequently takes us right up to the state of the art in technical innovation, be it reinforcement learning, distributed systems, generative AI, or deployment infrastructure. The defence industry is entering the most exciting phase of the technological development curve. Advances in our field of world are not incremental: Helsing is part of, and often leading, historic leaps forward

• In our domain, success is a matter of order-of-magnitude improvements and novel capabilities. This means we take bets, aim high, and focus on big opportunities. Despite being a relatively young company, Helsing has already been selected for multiple significant government contracts

• We actively encourage healthy, proactive, and diverse debate internally about what we do and how we choose to do it. Teams and individual engineers are trusted (and encouraged) to practise responsible autonomy and critical thinking, and to focus on outcomes, not conformity. At Helsing you will have a say in how we (and you!) work, the opportunity to engage on what does and doesn’t work, and to take ownership of aspects of our culture that you care deeply about

Nice to have

• Significant recent experience with React.

• Familiarity with backend interface tools like REST, GraphQL, gRPC/Protocol Buffers.

• Established understanding of modern JS bundlers, such as Vite, and experience maintaining frontend infrastructure.

• Experience with styling utility-class libraries such as TailwindCSS and building reusable React component libraries.

• Data visualization expertise (e.g., D3.js, custom charting, or complex dashboard design).

• Background in designing software for aerospace, defense, or AI end users.

What we offer

• A focus on outcomes, not time-tracking

• Competitive compensation and VSOP options

• Relocation support

• Social and education allowances

• Regular company events and all-hands to bring together employees as one team across Europe

• A hands-on onboarding program (affectionately labelled “Infraduction”), in which you will be building tooling and applications to be used across the company. This is your opportunity to learn our tech stack, explore the company, and learn how we get things done - all whilst working with other engineering teams from day one 

Helsing is an equal opportunities employer. We are committed to equal employment opportunity regardless of race, religion, sexual orientation, age, marital status, disability or gender identity. Please do not submit personal data revealing racial or ethnic origin, political opinions, religious or philosophical beliefs, trade union membership, data concerning your health, or data concerning your sexual orientation.

Notre Creative Studio recherche un·e Lead Email Developer (f/m/d) basé·e à Lille.

Après avoir déployé un système modulaire dans plus de 70 pays, notre défi pour 2026 est de migrer vers un modèle drag-and-drop "in-house" pour simplifier l'expérience utilisateur à l'extrême. Nous embauchons pour porter cette vision Inner Source et permettre à chaque coéquipier de créer des emails hyper-personnalisés en un temps record. Rejoins une équipe passionnée où le partage de connaissances et l'innovation technologique sont nos rituels quotidiens.

TA FUTURE CONTRIBUTION

En tant que pilier technique de l'équipe, tu seras responsable de l'évolution de notre plateforme (plus de 100 messages internationalisés et 200 blocs d’hyper-personnalisation). Ton rôle est de rendre nos outils accessibles à tous·tes les utilisateur·ices, quel que soit leur niveau technique.

• Tactique & Delivery : Transformer les besoins business en roadmaps techniques en binôme avec le Product Management.
• Architecture & Résilience : Concevoir un Email Design System capable d'encaisser 1 million d'envois quotidiens avec une robustesse à toute épreuve.
• Jeu collectif : Agir comme un "multiplicateur technique" en coachant les squads de développeurs partenaires via des revues de code et du mentorat.
• Excellence du Geste : Garantir la qualité logicielle (Atomic Design, Clean Code) et superviser l'implémentation du BDD pour des déploiements sans faute.
• Culture DevSecOps : Piloter les déploiements via des pipelines CI/CD optimisés et renforcer l'observabilité (monitoring/alerting).

Stack Technique

Decathlon est une organisation mondiale avec des hubs à Amsterdam, Paris, Lille et Nantes, proposant des solutions digitales pour 70 pays. Pour gagner ce match, voici ton "sac de sport" technologique :

• Email Framework : Framework Maizzle (basé sur tailwind) boosté aux stéroïdes (pour une agilité maximale).
• Email Templating : Salesforce Marketing Cloud (AMPScript, SSJS) "superchargé" par nos propres librairies maison.
• Langages de prédilection : HTML, CSS, TypeScript, Bash, Python.
• Outillage Full-Stack : Frontends basés sur React et Next.js, Backends et CLI reposant sur NestJs.
• Persistence & Data : PostgreSQL, Redis.
• Observabilité : Datadog pour ne rien laisser passer.
• Cloud & Infrastructure : GCP, Aiven, Docker, Kubernetes (K8S), Flux (GitOps).
• Qualité & CI/CD : GitHub, GitHub Actions, SonarCloud, Cucumber, Gherkin, Playwright.
• Jeu collectif : Slack, Google Suite, Confluence, Jira.

CE QUE TU APPORTES

• Expérience Terrain : Plus de 5 ans d'expérience en tant qu'Email Developer dans un contexte CRM international. Tu as déjà performé sur Salesforce Marketing Cloud ou un ESP de même envergure.
• Maîtrise du Geste : Expert·e en Atomic Design et en composition de blocs. Tu sais jouer avec TypeScript pour moduler ton code et créer des composants réutilisables à l'infini.
• Vision Tactique : Une capacité hors pair pour orchestrer des parcours emails automatisés à grande échelle via un ESP.
• Esprit "You build it, you run it" : Pour toi, la responsabilité ne s'arrête pas au coup de sifflet final. Tu assures le monitoring, l'alerting et l'analyse d'incidents (RCA) avec un Operational Mindset d'acier.
• Excellence Technique : Adepte de l'entraînement rigoureux, tu maîtrises la CI/CD, le TDD/BDD et toutes les couches de tests (Unitaires, Intégration, Charge).
• Capitaine de Jeu : Tu sais driver des projets transverses et faire monter l'équipe en compétences grâce à des revues de code exigeantes et bienveillantes.

Les "Game Changers" (Le petit plus qui fait la différence)

• Infrastructure & Cloud : Tu es à l'aise avec Kubernetes, Terraform et GCP pour garantir une scalabilité mondiale.
• Profil Multi-sport (Full-Stack) : Tu maîtrises le Front et le Back (Hexagonal Architecture, Clean Code) sur au moins un framework mainstream.
• Culture Data : Tu as un intérêt marqué pour la Data Stack. Car tu le sais : pas de data, pas de personnalisation, pas de victoire !

CE QUE NOUS T’OFFRONS

• 2 jours de télétravail par semaine ;
• Possibilité de travailler dans l'un des bureaux de Decathlon Digital à Lille, Paris ou Amsterdam ;
• Matériel fourni en accord avec tes missions et nos engagements sociétaux (Mac, Windows, ou Chromebooks) ;
• Une équipe de projet locale au sein d'un réseau mondial (possibilité de carrière internationale) ;
• Développement des compétences et accompagnement (diversité des projets, certifications techniques dès la première année, formations internes et externes, etc.) ;
• Package de rémunération (participation des employés aux actions de l'entreprise, bonus mensuels/trimestriels).