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.