Data Engineer - Foundational

Harmattan AI

ABOUT US Harmattan AI is a next-generation defense prime building autonomous and scalable defense systems. Following the close of a $200M Series B, valuing the company at $1.4 billion, we are expanding our teams and capabilities to deliver mission-critical systems to allied forces. Our work is guided by clear values: building technologies with real-world impact, pursuing excellence in everything we do, setting ambitious goals, and taking on the hardest technical challenges. We operate in a demanding environment where rigor, ownership, and execution are expected. ABOUT THE ROLE As a Machine Learning Engineer on our Foundational team in Paris, you will build the "brain" of our tactical robots. You will design and scale large-scale, multi-modal foundational models that learn robust representations of the battlefield using Self-Supervised Learning (SSL) from massive amounts of unlabelled Electro-Optical (EO) and Infrared (IR) data. Your work provides the critical foundational weights that our Edge AI team distills into hyper-accurate models running on tactical hardware.   RESPONSIBILITIES * Multi-Modal SSL Architecture Design: Design neural network architectures (Vision Transformers) and loss functions (Masked Autoencoders, Contrastive Learning) to jointly learn from paired and unpaired EO and IR data. * Distributed Training Infrastructure: Manage and optimise training pipelines across multi-node GPU clusters, handling mixed-precision training and data loading. * Representation Evaluation: Develop metrics and linear-probing benchmarks to prove the latent space captures useful semantic features before distillation. * Data Strategy: Audit existing EO/IR data lakes and implement cross-attention mechanisms to fuse diverse sensor features. * Cross-Functional Collaboration: Sync with Data Engineers on ingestion pipelines and collaborate with the Edge AI team to ensure high-performance model handoffs. Candidate Requirements * Educational Background: A PhD or a highly research-focused MS in Computer Science, Machine Learning, Computer Vision, or Applied Mathematics. * Proven Experience: Minimum of 5-6 years of experience for senior levels. Experience training and scaling deep learning vision models (ViTs, CNNs) from scratch in multi-GPU/multi-node environments. Successful application of novel SSL or multi-modal architectures (e.g., CLIP, MAE, DINO) to real-world, non-standard imaging data (IR, SAR, or hyperspectral). * Technical Proficiency: Hardcore PyTorch engineering skills combined with deep mathematical intuition for representation learning. Knowledge of system-level languages (C++, Rust, or Go) and resource optimisation for edge computing. * Complexity & Leadership: Ability to architect state machines for fault-tolerant data pipelines and mediate technical trade-offs between hardware and algorithm teams. * Commitment & Mindset: 100% dedication to Harmattan AI’s mission of providing an ethical defence edge to allied countries. A hybrid researcher-engineer mindset that treats data quality as seriously as algorithm design We look forward to hearing how you can help shape the future of autonomous defense systems at Harmattan AI.

Voodoo

ABOUT VOODOO Founded in 2013, Voodoo is a tech company that creates mobile games and apps with a mission to entertain the world. Gathering 800 employees, 7 billion downloads, and over 200 million active users, Voodoo is the #3 mobile publisher worldwide in terms of downloads after Google and Meta. Our portfolio includes chart-topping games like Mob Control and Block Jam, alongside popular apps such as BeReal and Wizz. TEAM The Engineering & Data team builds innovative tech products and platforms to support the impressive growth of their gaming and consumer apps which allow Voodoo to stay at the forefront of the mobile gaming industry. The Voodoo Ad-Network is an autonomous product group of around 60 highly driven professionals with an ambitious mission: building top-tier ad network services. Our primary goal is to leverage Voodoo’s massive first-party data ecosystem to optimize and scale monetization. We are in a rapid growth phase, expanding into new ventures such as opening to external inventory, penetrating the external advertiser market, and driving social network monetization following our recent acquisition of BeReal. To support this incredible trajectory and promising early results, we are scaling our team. The Feature Platform Team is the foundational infrastructure engine empowering our ML Ads Recommendation capabilities. Drawing inspiration from industry-leading feature stores, we build and maintain the unified data layer for our machine learning features. Our mission is to accelerate the ML lifecycle by providing a unified, scalable, and highly available architecture for computing, storing, and serving batch, real-time, and on-demand features. Beyond just building the infrastructure, we are a highly proactive team that continuously explores new data signals and feature engineering opportunities to push the boundaries of our targeting performance. This role is a hybrid position, either based in Helsinki, Paris or Strasbourg. ROLE We’re looking for a Senior Data Engineer to join our Feature Platform Team. You will be joining a dedicated squad of Data and ML Engineers focused on guaranteeing consistency across offline training and online inference, eliminating training-serving skew, and enabling our Data Scientists to seamlessly and rapidly deploy the next generation of high-performing models. In this role as a Senior Data Engineer, your scope extends far beyond classical data engineering. You will be responsible for managing both the offline and online components of our machine learning architecture. This means bridging massive-scale data processing (handling both heavy batch jobs and subsecond real-time feature updates) with high-load online services that must process and return features for inference with strict low latency. * Architectural Ownership: Take end-to-end ownership of highly visible projects from initial ideation to production release. This includes feature scoping, timeline estimation, architecture design, and benchmarking next-generation technologies. * Proactive Data Innovation: Go beyond passive implementation by actively partnering across the entire data lifecycle. You will deeply understand the downstream Data Science domain to discover high-impact feature opportunities, while also collaborating closely with upstream data engineering teams to understand ingestion mechanisms (right up to the SDK and Bidding platforms) to unlock and integrate new data signals. * ML Infrastructure & Feature Platform: Collaborate closely with Data Scientists and ML Engineers to design, scale, and optimize core components spanning both offline training and online inference, including our Feature Store (supporting batch, streaming, and low-latency on-demand computation) and engines for on-demand training dataset generation. * Pipeline Engineering: Build, maintain, and optimize mission-critical data pipelines spanning both extensive batch processing and continuous real-time streams (ensuring subsecond feature updates) to adapt to ever-evolving business and machine learning needs. * High-Performance Online Services: Actively build and maintain the high-load backend applications that power our ML model serving, ensuring they can process and return features with low latency and high availability under heavy traffic. * Scalability & Performance: Work hand-in-hand with our infrastructure teams to guarantee the reliability, security, and immense scalability required for an ad-network ecosystem. * Agile Collaboration: Thrive in a fast-paced agile environment with rapid decision-making processes. You will collaborate daily with back-end developers, data scientists and product managers. * Mentorship & Team Culture: You will actively contribute to our engineering culture, share knowledge, and ensure every team member feels comfortable, supported, and empowered to grow in their role. PROFILE We are looking for a Senior Data Engineer who deeply understands both the data lifecycle and the specific challenges of putting machine learning models into production at scale. * 6+ years of proven experience as a Data Engineer, ML Engineer, Backend Engineer, or a closely related role in a high-scale environment. * Big Data & Streaming Mastery: Extensive hands-on experience working with Flink or Spark at scale. Deep expertise in Flink (or similar stateful streaming platforms) as you will be a key contributor in scaling our real-time streaming architecture. * Coding Proficiency: Advanced expertise in Python for robust ETL pipelines and custom feature-definition SDKs/DSLs * Experience or a strong willingness to work with Golang for building high-performance, low-latency backend applications as well as familiarity with Java is highly valued for our Flink streaming workloads. * Data Architecture: Deep understanding of modern Data Lakehouse design principles, open table formats (like Iceberg), optimization techniques, and data modeling. * Cloud & DevOps: Strong hands-on experience with a major cloud platform (AWS, GCP, Azure, etc.), though AWS is our preferred environment. Familiarity with DBT for data pipeline transformation is a plus. * ML Production Awareness: You have a solid grasp of the unique challenges involved in running ML models in production, including working with Feature Stores, mitigating training-serving skew, and model monitoring. * System Design: You are highly familiar with topics surrounding system scalability, high availability/reliability, low-latency API design, and security best practices. OUR STACK * Languages: Python (ETL & SDKs), Golang (High-Performance Online Services), Java (Flink) * Processing & Orchestration: Spark, Flink (Real-time Streaming), Airflow, DBT * Storage & Infrastructure: Apache Iceberg, Amazon Web Services (AWS), Kubernetes, Terraform BENEFITS * Competitive salary based on experience * Swile Lunch voucher * Gymlib (100% covered by Voodoo) * Premium healthcare coverage with SideCare, 100% covered for you and your family * Wellness activities in our Paris office * Remote Fridays

Alma

🧡 ABOUT ALMA At Alma, we believe sustainable commerce depends on fair, well‑balanced trade. Because finance plays a pivotal role in business, our mission is to put it back in its rightful place - serving merchants and consumers. Our installment and deferred payment solutions help merchants boost sales by 20% or more, increase customer loyalty, and deliver a seamless shopping experience - without encouraging bad debt. As the buy now pay later leader in France and active in 10 European countries, we've empowered over +25,000 merchants and 10 million consumers. With 380+ Almakers and €100M+ ARR, Alma is scaling rapidly across Europe as a member of the Next40, and we're just getting started!   👐 ABOUT THE TEAM  The Developer Experience (DevX) squad is part or the Engineering’s Platform Tribe. The Platform Tribe groups the DevX squad and the Site Reliability Engineering quad. The members of the tribe are responsible for building the foundational infrastructure, security layers, and core systems that empower Alma's entire product and engineering organization to scale reliably.  You will join a dedicated squad focused entirely on the daily lives of our engineers: Our mission is to eliminate friction from a developer's machine all the way to production. We build, optimize, and maintain the delivery systems, local development environments, and CI/CD automation that allow our product teams to ship high-quality code safely, frequently, and with absolute confidence. We operate in a highly dynamic, polyglot environment. We are looking for an engineer driven by technical curiosity, who loves exploring new tools and technologies to continuously elevate our engineering standards. This is a full-time position, based in Paris or fully remote in France.   💼 ABOUT THE JOB * Own and continuously optimize our CI/CD pipelines and delivery workflows, ensuring fast feedback loops and secure deployments. * Build and evolve the local developer experience, making it seamless for engineers to spin up, test, and debug services locally across a variety of languages and frameworks. * Own and maintain part of our cloud infrastructure and container orchestration platforms using Terraform and Kubernetes. This will also require participating in identifying and solving infrastructure-related production issues and performance troubleshooting, upgrading our platforms for long-term resilience. * Be a technical referent and drive engineering standards forward by acting as a trusted partner for product engineering squads on delivery and infrastructure best practices, sharing expertise and providing guidance. * Encourage a culture of technical curiosity by frequently evaluating, benchmarking, and prototyping emerging technologies to bring the best tool sets to the team and promoting a culture of continuous learning across the org.   🧰 YOU WILL WORK WITH Python, TypeScript, PHP, Docker, Kubernetes, Terraform, GitHub Actions, GCP, Postgres and Datadog.   🧩 ABOUT YOU To succeed in this job * You've built at least 5 years of experience in a relevant role, ideally in DevOps or Platform Engineering. * You take ownership of cross-functional infrastructure initiatives, driving complex projects from design to delivery alongside multiple teams. * You have hands-on experience designing, building, and optimizing CI/CD pipelines end to end (GitHub Actions or equivalent). * You're comfortable building robust automation pipelines and modernizing local development environments. * You are fluent in french (primary working language) with a good level of English, for documentation, cross-team exchanges, and technical reading, writing as well as presenting. And it will be nice if you also * Have production-grade proficiency with Infrastructure as Code (not necessarily Terraform) and container orchestration (not necessarily Kubernetes). * Are familiar with an observability and monitoring stack (Datadog, Prometheus, or equivalent). * Have worked with local development environment tooling (Nix, mise, asdf, devenv, devcontainers, etc.). * Working knowledge of at least one language from Alma's stack (Python, TypeScript, or PHP), enough to read, debug, and contribute when needed. Don't meet every single requirement? At Alma, we believe great hires come from diverse paths. If this role excites you, we encourage you to apply. We value potential, curiosity and the ability to grow as much as experience.   🧘 WHAT’S IN IT FOR YOU If you join, you will be able to grow and impact on: * The infrastructure and tooling that directly shapes the productivity and confidence of every engineer at Alma. You'll have real ownership over your scope, the space to explore and prototype freely, and the support to take initiative. * The DevX squad, a dynamic, polyglot team where learning together is a core habit, not an afterthought. * Alma's growth across Europe, as the infrastructure you build directly enables us to scale reliably across 10 markets and more in the future, your work has a clear and measurable line to the business.   🤑 COMPENSATION & BENEFITS * Competitive salary based on 12 months * Profit-sharing and employee savings plan * Health insurance: 100% covered by Alma including family package * Disability insurance: 100% covered by Alma * Sport: partnerships with Gymlib and Classpass, or €30/month reimbursement for your sports activities * Maternity/paternity leave: salary maintained at 100% during leave with no seniority requirement. Return to work at 4/5 schedule paid at 100% for 8 weeks. * Sustainable Mobility Package (FMD): €544.80/year (excluding full-remote contracts) * Meal vouchers: €10/day, 50% covered by Alma * Mental health: free access to MindDay platform * Paid time off: 25 days/year ****(+ additional paid leave granted for employees on executive contracts) * Access to our Learning & Development Platform * 2 weeks of full remote possible per year in summer for people working in hybrid remote   🎯 INTERVIEW PROCESS * Video call with a Talent Acquisition team member to understand your path, motivation & present you the role. * Video call with your future manager to deep dive the role, the team, your profile and answer all your questions. * Case study presentation with 2 - 3 team members (ideally in house) to assess your practical knowledge**.** * Take-home coding test, followed by a remote feedback session. * Live system design interview to assess your practical and architectural knowledge. * A coffee chat with the squad you’ll join to further assess your skills and team fit.   🌍 DIVERSITY & INCLUSION At Alma, we believe that diversity fuels innovation and makes our community stronger. We are committed to building a workplace where every person feels seen, respected, and empowered to do their best work whatever their gender, background, ethnicity, age, sexual orientation, religion, disability or lived experience. As an equal opportunity employer, we welcome applicants from all walks of life, and all employment decisions are made based on qualifications, merit, and business needs.