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.