Senior Data & Platform Engineer

Who we areCryptoNext Security is a deeptech startup specializing in post-quantum cryptography. We help businesses and institutions prepare for a world where quantum computers will challenge today's security standards.Our clients include major financial institutions, defense actors, telecom operators, and global enterprises seeking to future-proof their cryptography.On a daily basis, you willAs Senior Data & Platform Engineer, you will lead the design, setup, and operation of the entire data backbone powering COMPASS, our observability and orchestration platform for post-quantum cryptography deployments.Your missions include:Data Modeling & GovernanceDefine and maintain the end-to-end data model for COMPASS (entities, relationships, vocabulary, lifecycle).Translate product requirements into robust database schemas, indexing strategies, and normalization/denormalization choices.Ensure semantic consistency and data governance rules across all services.Ingestion, Streaming &

StorageDesign, validate, and maintain ingestion pipelines using Kafka, ensuring data correctness and consistency.Define the canonical formats exchanged across Kafka (ingestion), PostgreSQL (storage), and Elasticsearch (search).Validate and standardize data structures produced by probes, sensors, and backend services.Backend Collaboration & API ContractsWork closely with backend teams to design API-level data contracts aligned with the data model.Optimize queries, indexes, and persistence strategies for real-time workloads and analytics.Observability & Data QualityContribute to platform-wide observability by defining structured logs, metadata standards, and ingestion patterns.Promote best practices for data quality, versioning, retention, and schema evolution.The skills you'll needMust-have15+ years of experience in software or data engineering in a distributed or complex environment.Master's degree from a French engineering school or European equivalent.Deep expertise in:Data modeling & relational schema designPostgreSQL administration & performance optimizationKafka (setup, topics/partitions, consumer groups, schema registry, monitoring)Elasticsearch / ELK stackStrong hands-on experience with:Stream processing architecturesETL/ELT workflowsData lifecycle managementProven ability to design data flows with clean, contract-based schemas.Strong commitment to code quality, documentation, and operational reliability.Fluency in English.BonusExperience with ClickHouse, Grafana, or Prometheus.Understanding of secure data handling and cryptographic components.Familiarity with AWS/GCP or hybrid on-prem architectures.Background in cybersecurity, observability, or high-throughput systems.Experience with large-scale data retention strategies and analytics workloads.The team you'll be joiningYou will work closely with:The R&D engineering team building CryptoNext's cryptographic and observability products.Backend engineers designing APIs and distributed services.The Head of

Engineering and CTO for architecture, strategy, and long-term product evolution.Product and QA teams to ensure data quality, reliability, and consistency across the platform.You will be the reference person for all data-related decisions and architecture within the COMPASS squad.Our recruitment processHR Intro - a first conversation to understand your background and expectations.Technical Interview with a senior engineer and the Head of Engineering (Kafka, PostgreSQL, ELK, data modeling).CTO Meeting - deep dive on architecture, COMPASS roadmap, and cultural fit.Offer & onboarding - welcome to CryptoNext!What's in it for you at CryptoNextJoin a deeptech company at the forefront of post-quantum cybersecurity.Build the core data infrastructure of a cutting-edge observability platform.Collaborate with world-class cryptographers and software engineers.Flexible hybrid/remote policy and office in central Paris.Competitive compensation aligned with seniority and expertise.Direct impact on a product used by major financial and defense clients.A chance to shape the future of quantum-safe data engineering. #J-18808-Ljbffr