Senior Software Engineer - Developer Tools

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: This role can be based at our office in Bothell, WA (US) or in Oxford, England (UK). Travel: Twice per year Job ID: 1452 The Role As a Senior Software Engineer for Developer Tools, you will be a key contributor to the software that connects quantum developers to IonQ's hardware. You will focus on contributing to quantum compiler tools and features that our users and internal research teams depend on to run applications. You will build tooling to give users deep insights into how their circuits are optimized and create intuitive, user-friendly interfaces for hardware-specific compiler passes, such as quantum error mitigation and quantum error correction, and ensure our tools are robust and well-documented. You will work closely with our Compiler, QEC, and Applications teams to take new features through development, testing, documentation, packaging, and release, and use software engineering best practices to document, distribute, and use them in quantum software applications. The Developer Tools team builds the critical software layer for the quantum ecosystem. In this role, you will help shape an ecosystem of tooling that turns high-level quantum circuits into optimized instructions for our quantum computers. Your work will directly impact the performance, reliability, and capabilities of quantum applications running on IonQ systems by focusing on the compiler's application-facing features and its connection to the hardware. The compiler is where quantum algorithms meet quantum hardware. Your work sits at the heart of this critical transformation. The tools you build will define how developers interact with our systems, enabling them to extract maximum performance, trust the compilation process, and tailor optimization strategies for their specific use cases. By focusing on compiler tools for applications, you empower developers to tackle real-world problems and push the boundaries of what's possible on quantum computers. You'll make advanced techniques accessible, from sophisticated error mitigation to hardware-aware compilation. This role offers a unique opportunity to work with world-class researchers and translate their innovations into production software that accelerates the path to quantum advantage for everyone. Responsibilities : Design, build, and maintain compiler toolchains, optimization tools, and circuit transformation libraries for developer-facing applications. Work with the Compiler and Applications teams to package, test, and document new compilation features for both internal and external developers. Architect and implement interfaces for hardware-specific compilation features, giving developers deeper control and visibility. Integrate automated error mitigation, quantum error correction, and other advanced compilation strategies into our cloud platform and SDKs. Maintain comprehensive docu