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Senior Data & Platform Engineer

Cryptonext Security

Cryptonext Security

Software Engineering
Paris, France
Posted on Nov 14, 2025

Who we are

CryptoNext 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 will

As 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 & Governance

  • Define 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 & Storage

  • Design, 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 Contracts

  • Work 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 Quality

  • Contribute 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 need

Must-have

  • 15+ 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 design
    • PostgreSQL administration & performance optimization
    • Kafka (setup, topics/partitions, consumer groups, schema registry, monitoring)
    • Elasticsearch / ELK stack
  • Strong hands-on experience with:
    • Stream processing architectures
    • ETL/ELT workflows
    • Data lifecycle management
  • Proven ability to design data flows with clean, contract-based schemas.
  • Strong commitment to code quality, documentation, and operational reliability.
  • Fluency in English.

Bonus

  • Experience 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 joining

You 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 process

  1. HR Intro – a first conversation to understand your background and expectations.
  2. Technical Interview with a senior engineer and the Head of Engineering (Kafka, PostgreSQL, ELK, data modeling).
  3. CTO Meeting – deep dive on architecture, COMPASS roadmap, and cultural fit.
  4. Offer & onboarding — welcome to CryptoNext!

What’s in it for you at CryptoNext

  • Join 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.