Senior Cloud Backend Software Engineer

Infleqtion is a global quantum technology company solving the world's most challenging problems. The company harnesses quantum mechanics to build and integrate quantum computers, sensors, and networks. From fundamental physics to leading edge commercial products, Infleqtion enables "quantum everywhere" through our ecosystem of devices and platforms. Our mission is to commercialise atom-based quantum products that provide orders of magnitude improvements in performance and computing applications.

Infleqtion has offices in the USA, United Kingdom and Australia. This is a full time position in our Kidlington and Harwell offices. Our flexible working policy enables all full time employees to work up to 2 days a week from home as work permits.

Infleqtion is seeking a Senior Cloud Backend Software Engineer to design and build scalable backend services that power both internal platform infrastructure and externally facing systems for our quantum technologies. This role focuses on developing cloud native microservice architectures, distributed APIs, and reliable backend systems that support experiment orchestration, data pipelines, device control workflows, and internal developer platforms. You will build and operate services that form the backbone of our quantum software platform, enabling scientists, engineers, and external users to interact with quantum hardware and experimentation workflows through robust, scalable infrastructure. The ideal candidate is comfortable building API driven services, asynchronous systems, and scalable data infrastructure deployed in containerised and orchestrated cloud environments.

The duties and responsibilities outlined below include essential functions of the role. Depending on business needs, this role may perform a combination of some or all of the following duties. Duties, responsibilities, and activities may change, or new ones may be assigned at any time.

• Design, develop, and operate cloud native backend services and microservice architectures supporting both internal engineering platforms and externally accessible APIs.
• Build Python based backend systems using modern frameworks such as FastAPI and SQLAlchemy to implement scalable, maintainable services.
• Architect and implement distributed systems that support experiment orchestration, telemetry collection, data ingestion, and device interaction workflows.
• Design backend systems with strong focus on reliability, scalability, observability, and fault tolerance, including monitoring, logging, tracing, and graceful degradation.
• Deploy and operate services using Docker containers, local development environments with Docker Compose, and production orchestration using Kubernetes.
• Collaborate with interdisciplinary teams including physicists, hardware engineers, and research scientists to translate experimental workflows into scalable software systems.
• Mentor junior engineers and promote best practices in backend architecture, distributed systems design, reliability engineering, and software development.
• Lead architecture discussions, design reviews, and code reviews to maintain high engineering standards and system maintainability.
• Contribute to platform reliability and operational excellence, diagnosing production issues, improving system performance, and strengthening infrastructure resilience.

• Bachelor's degree in Computer Science, Engineering, Applied Mathematics, Physics, or related field with 3+ years of professional software engineering experience.
• Strong experience developing backend systems in Python, particularly using modern frameworks such as FastAPI, SQLAlchemy, or similar tools.
• Experience designing and implementing and deploying distributed systems or microservice architectures, using tools including Docker, Docker Compose & Kubernetes.
• Experience designing systems for reliability, scalability, and operational robustness and using CI/CD pipelines, automated testing infrastructure, and deployment automation.
• Strong understanding of software engineering best practices, including testing, version control, debugging, observability, documentation, and maintainability.
• Strong communication and collaboration skills, with the ability to work effectively across interdisciplinary teams.
  

• Experience building distributed systems in cloud environments (AWS, GCP, Azure, or similar).
• Experience with message queues and event driven architectures (e.g., Kafka, RabbitMQ, NATS, or similar).
• Experience with database systems and data infrastructure, including relational databases, time series databases, and large scale data pipelines.
• Experience building Python packages with native extensions (Rust/C/C++).

Regardless of your interest in the quantum industry, you can take pride in the fact that Infleqtion is building an ecosystem of quantum technologies and commercial products, driving the industry towards the future. Studies reveal that while men apply for jobs when they meet an average of 60% of the requirements, women and other groups tend to apply only when they meet all the criteria. If you believe you have the potential but don't meet every single point in our job advertisement, please don't hesitate to contact us! We would love to chat with you and see how you could bring great value to our team. Our goal is to find exceptional individuals who can enrich our team culture, actively contribute, and have a genuine passion for their work. Here you have freedom to embrace your whole self: who you love, your gender identity and expression, skin colour, age, appearance, disability, neurodiversity, DNA, military/veteran status, citizenship, and other factors that make up who you are. Your uniqueness is valued, welcomed, and appreciated here. We are dedicated to providing a positive workplace and base all employment decisions on your qualifications, performance, merits, as well as business needs. We are proud to be an Equal Employment Opportunity Employer.

In addition to your base compensation, we offer a generous Total Rewards program which includes:

• Competitive salary
• Incentive Stock Option Plan
• Generous company 10% pension contribution regardless of employee contribution
• Unlimited PTO
• BUPA healthcare after probation period
• Cycle to work and Technology scheme