Principal Software Architect — Quantum Platform

Location: Remote within Europe, with regular presence in Bremen

Direct Reports: None initially; technical leadership across the engineering group

Mission

Own the architecture of the software platform on which Constructor Labs' quantum group builds. The platform drives physical quantum hardware end to end - calibration, orchestration, experiment execution and device state - and must work both in our own cloud and on customer premises, including restricted and air-gapped environments. The Principal Architect sets the technical direction, makes the structural decisions, and is the senior engineering voice in a group where research and engineering sit closely together.

Responsibilities

Pillar 1 Platform Architecture

• Own the end-to-end architecture across backend services, job orchestration, hardware abstraction and device state management.
• Define the interfaces between the scientific layer and the platform layer so physicists can work without engineering support.
• Make and carry the build-versus-buy and framework decisions; document them so they survive the people who made them.
• Lead the migration of the platform onto the Constructor technology stack.

Success Metrics and KPIs: architectural decisions documented and adopted, platform stability, migration delivered to plan.

Pillar 2 Hands-on Engineering

• Write production code in the core of the system, not only design documents.
• Own the hardest components personally - those where correctness and performance both matter.
• Set and enforce engineering standards: testing, review, structured logging, dependency governance.
• Remove single points of failure so no component has only one person who understands it.

Success Metrics and KPIs: test coverage, review discipline, bus factor above one on every core component.

Pillar 3 Working with Research

• Work day to day with research physicists, translating experimental workflows into software.
• Keep the research and engineering collaboration model intact as the group grows.
• Support the product function with realistic estimates and honest technical constraints.

Accountability: research team able to run experiments without engineering bottlenecks.

Requirements

Experience

• 10+ years building production software systems, with real depth in Python, C#/.NET or C++.
• Distributed systems, job scheduling, and interfacing with instruments or physical hardware.
• Track record as the senior technical voice in a small team.
• Delivered software into on-premise and restricted environments, not only cloud.

Skills & Competencies

• Able to hold an architecture in your head and explain it simply to people who are not engineers.
• Comfortable in a scientific domain. A physics degree is not required, genuine interest is.
• Pragmatic about trade-offs; able to ship rather than perfect.
• Strong written communication. Decisions that are not written down do not exist.

Education & Languages

• Degree in computer science, physics, engineering or equivalent practical track record.
• Fluent English. German useful, not required.

What This Role Is (and Is Not)

This role IS

• Deeply hands-on, with real authority over technical direction.
• Central to everything the quantum group builds.
• A role where you will have peers and a platform behind you.

This role is NOT

• A management track role.
• An architecture-committee or advisory position.
• A role where someone else writes the hard code.