Quantum Software Developer (Fault Tolerance)

About QC Design:

QC Design is a quantum computing software startup helping quantum hardware teams build scalable, useful quantum computers.

We build Plaquette™, a design tool for fault-tolerant quantum computing (FTQC), think of it as an AutoCAD-style software for quantum error correction (QEC) and fault tolerance. Plaquette brings together quantum error-correction code libraries, hardware-realistic noise models, decoding workflows, and multiple simulation backends so teams can design and evaluate FTQC architectures under realistic hardware constraints.

Our customers include over 10% of the world’s quantum hardware companies across all hardware platforms. They rely on Plaquette to explore architectures, compare tradeoffs, and plan hardware-efficient paths to logical qubits. We continuously evolve Plaquette based on what customers need next.

We are a 12-person team of scientists and engineers from across 6 countries. Our strengths are in quantum software, hardware, and fault tolerance.

Role and responsibilities:

We want to strengthen Plaquette’s position as the ultimate design tool for fault-tolerant quantum computers. We are hiring a quantum software developer to contribute to these efforts.

In this role, you will be responsible for the full lifecycle of feature development: You will listen to customers, work with the team to understand the underlying FTQC concepts, and deliver reliable, performant implementations across our Python orchestration layer and C++ simulation backends.

This is a quantum-first software role. This role is ideal for someone who likes to code; has a strong quantum computing background; and is excited to go deeper on error correction and fault tolerance through real product work.

What you will do:

• Read and understand relevant aspects of quantum computing literature with an emphasis on fault-tolerance simulation and decoding workflows
• Translate customer needs into clear technical plans and product requirements
• Design and implement new Plaquette capabilities, including APIs, workflows, and integration between modules
• Productionize prototype code coming from research-focused teammates, improving performance, interfaces, tests, and maintainability
• Raise engineering quality across the codebase through reviews, CI, benchmarking, and careful correctness practices
• Improve user experience via documentation, examples, tutorials, and reproducible benchmark cases
• Use modern AI coding tools effectively while preserving reliability, clarity, and test coverage

What we’re looking for:

• Degree in physics, computer science, mathematics, or a related field (MSc, PhD or equivalent experience)
• Experience with quantum computing and comfort with QEC and FT concepts, e.g., stabilizer formalism, Clifford circuits, Pauli noise models, syndrome extraction, and decoding workflows
• Strong proficiency in Python and interest in software engineering fundamentals
• Comfort working with performance sensitive codebases; C++ is a plus
• Experience collaborating on production codebases (code review, testing, CI), or contributions to open source projects
• Demonstrated ability to learn fast and adapt to the changing demands of a startup environment
• High ownership mindset, focussing on what moves the company and customers forward, and you proactively support the team where needed
• Clear written communication, especially when turning complex concepts into docs, examples, or internal notes
• Comfort in using AI tools (Codex, Claude Code, AI reviews, etc.) without compromising on code quality or reliability is a plus

What we offer:

• A chance to shape the tool used by the world’s top quantum companies
• The possibility to ship quickly and get real customer feedback
• Competitive salary and meaningful equity
• Flexible working hours and hybrid work options
• A supportive environment with strong technical peers and real customer feedback loops

Location:

In person at Ulm, in Germany. Hybrid options are available.

Deadline:

11:59pm on 31 January 2026 Anywhere on Earth