Software Engineer

The Software team is here to assist and facilitate the work of the research teams towards building a quantum computer. As a Senior Software Engineer, you will be at the forefront of shaping the future of quantum measurement and help build the framework that runs experiments on quantum computers. Your expertise will drive the development and innovative solution that bridges the gaps between our R&D and engineering, enabling breakthrough in quantum technology., * Lead the design and development of our core quantum measurement software framework, ensuring high performance and long-term maintainability

• Partner with our R&D and other engineering teams at C12 to translate complex experimental requirements into robust, scalable software solutions
• Define and document the unified architecture for instrument control, high-throughput data storage, and measurement orchestration to support framework growth
• Champion rigorous software practices, including comprehensive code reviews, proactive design discussions, and robust CI/CD and automated testing pipelines
• Take ownership of the full software lifecycle, delivering robust, secure, and scalable solutions that meet the rigorous demands of quantum R&D
• Cultivate a culture of continuous learning by mentoring junior engineers and leading by example in code quality and system design

• You have 5+ years of experience building robust backend systems or data-intensive applications
• You are comfortable working with Python as a primary language; if coming from another background, you are eager to master the ecosystem
• You’re familiar or comfortable working with message brokers (e.g., RabbitMQ, ZeroMQ, Kafka) and relational databases (PostgreSQL), SQLAlchemy, etc
• Prior experience with orchestration tools like Prefect or Airflow is a strong plus
• A background in physics, engineering, or another quantitative field is a strong plus
• You are curious, adaptable, ready to discover new languages/frameworks/apis
• A problem solver that tries to use the best tool for the job
• You communicate clearly in English and work well in collaborative development environments, * You like hands-on work and technology
• You want to contribute to achieving landmark results in quantum computing, making a difference in the emerging quantum technologies
• You want to work within a team of 80+ people with various backgrounds in nanofabrication, quantum electronics, and carbon nanotube science to create a revolutionary quantum computing processor
• You want to thrive in an exceptional scientific environment with several industrial and academic partners
• You share our values (excellence, scientific integrity, diversity, curiosity, and care) and want to help us define our product-focused culture and ambition to accelerate

• 60,000 euros - 78,000 euros yearly base salary
• Stock options for every employee (BSPCE/ESOP)
• Sponsored trip to conferences around the world
• A highly dynamic international team
• Swile meal vouchers
• Mental health support with moka.care
• Training budget/ Annual Learning & Development Allowance
• Sabbatical leave (after 2 years in the company)
• Vibrant office culture (two office spaces in the heart of Paris, team lunches, offsite events, Friday breakfasts..)

Founded in 2020 and based in the heart of Paris, C12’s mission is to be at the center of one of the biggest technological breakthroughs of the century and change the course of history by building a universal quantum computer. At C12, we believe that achieving a true breakthrough in quantum computing requires rethinking the fundamentals. That’s why our founders-deeply rooted in academic and engineering excellence-have chosen carbon nanotubes as the building blocks of our quantum processors. This ultra-pure material dramatically reduces error rates, boosts performance, and minimizes hardware overhead-key ingredients for scalable, fault-tolerant quantum computing. By crafting a unique approach that scales, we aim to revolutionize quantum computing just as silicon transformed classical computing. Since our founding, we’ve raised over €25 million in funding, published 11 scientific papers, and secured 8 patents. Today, our fast-growing team of 80+, including 25 PhDs, has over 26 nationalities represented. We have our own cutting-edge lab spaces in Paris’ historic Panthéon district, where scientists, engineers, and innovators work side-by-side to tackle some of the most exciting technical challenges of our time. If you’re passionate about shaping the future of quantum technology and want to make a real impact, C12 offers a unique environment to grow, learn, and innovate.