About IonQ: IonQ, Inc . [NYSE: IONQ] is the world’s leading quantum platform and merchant supplier - delivering integrated quantum solutions across computing, networking, sensing, and security. IonQ’s newest generation of quantum computers, the IonQ Tempo, is the latest in a line of cutting-edge systems that have been helping customers and partners including Amazon Web Services, and AstraZeneca achieve 20x performance results and accelerate innovation in drug discovery, materials science, financial modeling, logistics, cybersecurity, and defense. In 2025, the company achieved 99.99% two-qubit gate fidelity, setting a world record in quantum computing performance . Headquartered in College Park, Maryland, IonQ has operations in California, Colorado, Massachusetts, Tennessee, Washington, Italy, South Korea, Sweden, Switzerland, Canada, and the United Kingdom. Our quantum computing services are available through all major cloud providers, while we also meet the needs of networking and sensing customers across land, sea, air, and space. IonQ is making quantum platforms more accessible and impactful than ever before. Location: Oxford, UK Office commitment: Hybrid The Role: We are looking for a highly technical Senior Software Engineer to join our System Orchestration team in System Software at Oxford Ionics. In this role, you will be responsible for building and operating the software that keeps our systems calibrated, decides what they do next and keeps the record of what they did, contributing to the team's mission of keeping our quantum computers running useful work around the clock. The trapped-ion quantum computers we are building will control 10,000 ions within two years, and all of that has to be kept in tune - settings that drift over minutes, hours and days. Without it a computer does not stop; it quietly starts producing invalid output. Calibration routines, scientists' experiments and customer workloads all compete for physical hardware, and our team builds the control plane that arbitrates that: it schedules and prioritises programs, hands exclusive access to one at a time and takes it back cooperatively, streams results while a program is still running, and keeps the record of everything that ran. It runs on every quantum computer in our fleet. Its job is to keep that machine busy and productive: running quantum programs rather than waiting in between, and running them in spec - on a machine still hitting the fidelity it is meant to hit. The ambition is for that to run without a person in the loop: machines that assess their own readiness, call for the calibrations they need, and keep a full history of how they were tuned. You'd work closely with the runtime team who own real-time control, the systems teams who build and maintain our quantum computers, and the operators and scientists who run them. This is a hands-on engineering role and stays that way as you grow in it. You'll play an important part in shaping the services that support our work in building the world's most advanced quantum systems. Previous exposure to quantum systems is not required. Responsibilities : In this position, you will work on a service or subsystem of the control plane end to end, supporting the effective delivery of software every machine in the fleet depends on. You'll have the opportunity to set how it behaves under failure and to move live systems onto it safely, contributing directly to the success of the System Software function. Key responsibilities include: - Own a service or subsystem end to end - API design, implementation, rollout and ongoing operational health. - Build closed-loop behaviour that acts on measured system state without a person in the loop. - Design state machines and their persistence together, so that what survives a restart is a decision rather than an accident. - Make our services behave correctly under concurrency and partial failure.Move live systems onto new behaviour without losing data or interrupting work in flight. - Evolve our APIs, and bring the clients that depend on them along. - Strengthen observability, health checking and alerting.Raise the standard of the code around you through review, and bring less experienced engineers on by working alongside them. Requirements: To be successful, you will need experience building stateful services that stay correct under failure, and a track record of changing a load-bearing system while people depend on it. We're looking for someone who can own a problem area with little supervision and contribute effectively within a fast moving, highly technical team. You'd be a great fit with: - Strong systems engineering skills. Our System Orchestration layer is written in Rust, so either solid Rust experience or deep proficiency in another systems language and the appetite to work in a Rust codebase, including async programming. - Experience designing and operating networked services (such as gRPC or REST), with a real grasp of error handling, observability and failure modes. - Real experience with a relational database as a source of truth - schema design, migrations against live data, and transactions. We use PostgreSQL. - A track record of getting lifecycle and concurrency right: state machines, timeouts, leases, retries, and the failure modes that only show up under load. - Experience with a scheduler, workflow engine or job queue - Temporal, Airflow, Celery, Slurm, or one you built - or with event-driven systems that react to changes in state. - A habit of settling design questions in writing, with options weighed as peers. - Comfort owning the production behaviour of what you build, not just its correctness in test. - Excellent communication skills both within software and across disciplines. - An interest in helping other engineers get better at the craft, without wanting to stop building yourself. Additional useful experience would include running containerised services in production, Kubernetes, distributed tracing, closed-loop systems that act on measured state, and scientific computing or research facilities. Benefits Be part of a team that’s shaping the future of quantum. We offer more than just a role, you’ll join a world class community of scientists, engineers and innovators working to unlock the full potential of quantum computing. We offer a range of benefits, including opportunities to further your career alongside industry leaders, a competitive salary with IonQ stock options, an annual performance bonus, generous annual leave, flexible hybrid working, private medical and dental insurance for you and your family, and much more. Join us and be part of the future of quantum computing. We’re proud to be an equal opportunity employer and welcome applicants from all backgrounds. Compensation will vary based on individual factors such as education, qualifications, and experience of the final candidate(s), specific office location, and calibration against relevant market data and internal team equity. Posted base salary figures are subject to change as new market data becomes available. Our benefits include comprehensive medical, dental, and vision plans, matching 401(k), unlimited PTO and paid holidays, parental/adoption leave, legal insurance, and a home technology stipend. Details of participation in these benefit plans will be provided when a candidate receives an offer of employment. At IonQ, we believe in fair treatment, access, opportunity, and advancement for all while striving to identify and eliminate barriers. We empower employees to thrive by fostering a culture of autonomy, productivity, and respect. We are dedicated to creating an environment where individuals can feel welcomed, respected, supported, and valued. We are committed to equity and justice. We welcome different voices and viewpoints and do not discriminate on the basis of race, religion, ancestry, physical and/or mental disability, medical condition, genetic information, marital status, sex, gender, gender identity, gender expression, transgender status, age, sexual orientation, military or veteran status, or any other basis protected by law. We are proud to be an Equal Employment Opportunity employer. US Technical Jobs. The position you are applying for will require access to technology that is subject to U.S. export control and government contract restrictions. Employment with IonQ is contingent on either verifying “U.S. Person” (e.g., U.S. citizen, U.S. national, U.S. permanent resident, or lawfully admitted into the U.S. as a refugee or granted asylum) status for export controls and government contracts work, obtaining any necessary license, and/or confirming the availability of a license exception under U.S. export controls. Please note that in the absence of confirming you are a U.S. Person for export control and government contracts work purposes, IonQ may choose not to apply for a license or decline to use a license exception (if available) for you to access export-controlled technology that may require authorization, and similarly, you may not qualify for government contracts work that requires U.S. Persons, and IonQ may decline to proceed with your application on those bases alone. Accordingly, we will have some additional questions regarding your immigration status that will be used for export control and compliance purposes, and the answers will be reviewed by compliance personnel to ensure compliance with federal law. US Non-Technical Jobs. Due to applicable export control laws and regulations, candidates must be a U.S. citizen or national, U.S. permanent resident (i.e., current Green Card holder), or lawfully admitted into the U.S. as a refugee or granted asylum. Accordingly, we will have some additional questions regarding your immigration status that will be used for export control and compliance purposes, and the answers will be reviewed by compliance personnel to ensure compliance with federal law. If you are interested in being a part of our team and mission, we encourage you to apply!