Senior Software Engineer - Quantum Computing

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. Your role at C12 Quantum Electronics: 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. Key responsibilities: Lead the design and development of our core quantum measurement software framework, ensuring high performance and long-term maintainabilityPartner with our R&D and other engineering teams at C12 to translate complex experimental requirements into robust, scalable software solutionsDefine and document the unified architecture for instrument control, high-throughput data storage, and measurement orchestration to support framework growthChampion rigorous software practices, including comprehensive code reviews, proactive design discussions, and robust CI/CD and automated testing pipelinesTake ownership of the full software lifecycle, delivering robust, secure, and scalable solutions that meet the rigorous demands of quantum R&DCultivate a culture of continuous learning by mentoring junior engineers and leading by example in code quality and system design About you: You have 5+ years of experience building robust backend systems or data-intensive applicationsYou are comfortable working with Python as a primary language; if coming from another background, you are eager to master the ecosystemYou’re familiar or comfortable working with message brokers (e.g., RabbitMQ, ZeroMQ, Kafka) and relational databases (PostgreSQL), SQLAlchemy, etcPrior experience with orchestration tools like Prefect or Airflow is a strong plusA background in physics, engineering, or another quantitative field is a strong plusYou are curious, adaptable, ready to discover new languages/frameworks/apisA problem solver that tries to use the best tool for the jobYou communicate clearly in English and work well in collaborative development environments What we offer: 60,000 euros - 78,000 euros yearly base salaryStock options for every employee (BSPCE/ESOP)Sponsored trip to conferences around the worldA highly dynamic international teamSwile meal vouchersMental health support with moka.careTraining budget/ Annual Learning & Development AllowanceSabbatical leave (after 2 years in the company)Vibrant office culture (two office spaces in the heart of Paris, team lunches, offsite events, Friday breakfasts..) You should join us if... You like hands-on work and technologyYou want to contribute to achieving landmark results in quantum computing, making a difference in the emerging quantum technologiesYou 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 processorYou want to thrive in an exceptional scientific environment with several industrial and academic partnersYou share our values (excellence, scientific integrity, diversity, curiosity, and care) and want to help us define our product-focused culture and ambition to accelerate We still encourage even if you don’t meet all the requirements. Rest assured, we are committed to finding the right fit for our team and are open to adjusting compensations based on skills and experiences. Applications from women are especially welcomed! We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.