Junior Software Engineer

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 our 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 includes 55+ people, with 20+ PhDs and over 20 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 :

Our software team is looking for a junior software engineer to help build and expand the web applications that power our quantum computing research. You'll work directly with our Senior Software Engineer to develop and maintain the internal tools our scientists and engineers rely on daily to track fabrication, nanoassembly and measurement activities.

Primary focus: Internal web application development (70%)

• Maintain and expand our organizational web platform used for research coordination and activity tracking
• Implement new features based on feedback from research teams
• Build intuitive interfaces that help scientists track experiments and collaborate effectively
• Ensure application reliability and performance as our research activities scale
  
  
  

Collaborative problem-solving (20%)

• Work closely with quantum researchers to understand their workflow needs
• Translate research requirements into practical software solutions
• Help identify and implement tools that accelerate our path to building a quantum computer
  
  
  

Technical growth and innovation (10%)

• Engage in two-way code reviews—reviewing both your Senior’s and having yours reviewed
• Propose and discuss new frameworks, design patterns, and architectural improvements
• Stay current with web development best practices and emerging technologies
• Contribute your fresh perspective on technical decisions
  
  
  

About you:

• Strong interest and foundational skills in full-stack web development
• Familiarity with JavaScript/TypeScript ecosystem
• Ability to build applications end-to-end
• Good command of English (verbal and written)
• Genuine curiosity about new technologies and frameworks
• Interest in quantum computing
  
  
  

Big plus:

• Experience with React, Vue or NestJS
• Understanding of RESTful APIs and database design
• Familiarity with modern web development tools (npm, webpack, etc.)
  
  
  

What we offer:

• Flexible rhythm of remote work
• Stock options for every employee (BSPCE/ESOP)
• Two incredible office spaces in the heart of Paris (both next to the famous Panthéon!)
• Sponsored trip to conferences around the world
• A highly dynamic international team
• Swile meal vouchers
• Breakfast for all every Friday
• Mental health support with moka.care
• Training budgets/ Annual Learning & Development Allowance
• Sabbatical leave (after 2 years in the company)
  
  
  

You should join us if...

• 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 55-people team 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
  
  
  

C12 encourages all who feel qualified to apply, recruitment decisions are based solely on qualifications, skills, knowledge and experience. Applications from women are particularly welcomed.