Senior Software Engineer: Architecture and Engineering Practices

Qilimanjaro Quantum Tech; Barcelona; On-site; EUR 90,000 - 120,000; Full time

Benefits offered by this job

Cobee flexible compensation

Flexible working hours

Strong mentorship and technical growth

Job summary

Qilimanjaro Quantum Tech, a Barcelona-based quantum computing company, seeks a Senior Software Engineer to design and build software for quantum hardware control, SDKs, and related tooling. You will be part of a hands-on team, turning architecture decisions into maintainable code and improving development workflows.

You will mentor colleagues, collaborate across departments, and contribute to scalable software initiatives in a fast-growing quantum startup in Barcelona.

Qualifications

• Hands-on software engineer role building software for quantum computing.
• Experience turning architecture decisions into tested, maintainable code.

Responsibilities

• Design and implement maintainable components, interfaces and migrations, documenting trade-offs and validating changes with technical owners.
• Collaborate with hardware-control software and SDK teams on shared architecture and tooling.
• Translate engineering practices into working examples and automated checks for tests, docs, dependencies and reviews.
• Improve workflows from need through implementation, verification and handover; mentor others.

Skills

Software design

Code maintenance

Mentoring

Cross-team collaboration

Architecture judgment

Experience with AI-assisted tooling

Job description

Qilimanjaro Quantum Tech is a Barcelona-based quantum computing company building full-stack analog quantum computers on superconducting fluxonium qubits.

Qilimanjaro designs, builds and operates the complete stack: the quantum hardware, the control layer, and the software that orchestrates it.

What we are looking for

We are looking for a Senior Software Engineer to design and build software for quantum computing and improve our engineering practices. You will join the Software team in the department developing software to control quantum hardware, and work across that department and the one developing software development kits and programming tools. You will report to the department’s Team Lead, who is responsible for people management, and collaborate with its Tech Lead and the division’s Staff Engineer on technical direction.

This is a hands‑on individual contributor role: you will turn architecture decisions into tested, maintainable code, improve development workflows and mentor through implementation and review. You should be interested in quantum computing and willing to learn the domain needed for your work; a physics background is not required.

• Design and implement maintainable components, interfaces and migrations, documenting trade-offs and validating changes with the relevant technical owners.
• Work with engineers developing hardware‑control software and software development kits on shared architecture, libraries, integration and developer tooling.
• Turn agreed engineering practices into working examples and automated checks for tests, documentation, dependencies and code review.
• Improve the workflow from a written need through implementation, verification and a supportable handover.
• Use AI tools for implementation and review where useful, and verify their output with tests, engineering judgment and the company’s approved tool and data policies.
• Partner with infrastructure and operations engineers on the services these workflows need; own the software code, test evidence and integration requirements.
• Mentor through pairing, design discussions and review, enabling other engineers to maintain the improvements.
• Track review waiting time, rework and defects alongside delivery lead time, and use that evidence to choose the next improvement.
• Demonstrated delivery of substantial, maintainable software through design, implementation, testing, release and support.
• Strong architecture and interface judgment, including compatibility, testability and incremental migration.
• Practical experience improving code review, automated testing and engineering workflows in a team.
• Ability to coordinate cross‑team implementation while respecting technical decision owners and agreed capacity.
• Evidence of mentoring and explaining technical trade‑offs clearly.
• Interest in quantum computing and commitment to developing relevant domain competence.
• Experience with scientific software, hardware‑connected systems, software development kits or reusable libraries.
• Experience introducing AI‑assisted engineering with evidence that quality and maintainability are preserved.
• Experience with reproducible experiments, hardware integration or quantum software.
• Familiarity with the languages and tools used by the team; the exact stack and Qilimanjaro's products can be learned during onboarding.

Diversity and Inclusion:

At Qilimanjaro, inclusion and equal opportunities are part of our people‑centric value. We are committed to creating a workplace where everyone feels valued and empowered to contribute, learn, and belong.

We offer:

• A unique opportunity to work on real superconducting quantum hardware
• Strong mentorship and technical growth
• Cobee flexible compensation (transportation, meals, and childcare support)
• Flexible working hours

You will:

Get the opportunity to build something amazing and unique, something that hasn't been done before

Work on ground‑breaking projects and possibly solve massive challenges on a global scale

Be at the intersection of research and industry, where biggest innovations happen

Make an enormous impact in a dynamic scale‑up rather than being a small cog in a big machine

Work with super smart, knowledgeable and yet, very friendly people in Barcelona, one of the best cities in the world (picture a lot of sun, amazing food and friendly locals)

Get to be part of a start‑up where growth on a company and individual level is the default

GDPR (General Data Protection Regulation):

DATA CONTROLLER: QILIMANJARO QUANTUM TECH S.L., B67429670, Carrer de Veneçuela, 74, 08019 Barcelona (BARCELONA), Data Protection Officer: qilimanjaro@delegado- datos.com.PURPOSES: Participation in recruitment processes and reference verification.LEGAL BASIS: Implementation of pre‑contractual measures.DISCLOSURES: None are an ticipated.DATA RETENTION: For the duration of the selection process.RIGHTS: You may exercise your rights of access, rectification, erasure, restriction, and data portability with the data controller. In case of any disputes, you may contact the AEPD (www.aepd.es).