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.