Senior Site Reliability Engineer in London

Circle is a financial technology company at the epicenter of the emerging internet of money, where value can finally travel like other digital data — globally, nearly instantly and less expensively than legacy settlement systems. This ground-breaking new internet layer opens up previously unimaginable possibilities for payments, commerce and markets that can help raise global economic prosperity and enhance inclusion. Our infrastructure – including USDC, a blockchain-based dollar – helps businesses, institutions and developers harness these breakthroughs and capitalize on this major turning point in the evolution of money and technology.

Circle is committed to visibility and stability in everything we do. As we grow as an organization, we’re expanding into some of the world’s strongest jurisdictions. Speed and efficiency are motivators for our success and our employees live by our company values: High Integrity, Future Forward, Multistakeholder, Mindful, and Driven by Excellence. We have built a flexible and diverse work environment where new ideas are encouraged and everyone is a stakeholder.

As a Site Reliability Engineer on the Blockchain Infrastructure team at Circle, you’ll play a pivotal role in designing, operating, and scaling our blockchain node infrastructure across multiple public cloud environments. You’ll work hands-on with Kubernetes, manage distributed blockchain systems, contribute to reliability engineering practices, and support our AI-driven tooling and supply chain management system. This role is ideal for someone who is deeply motivated, thrives in high-ownership environments, and is passionate about building resilient systems at scale to support a fast-growing blockchain platform. If you’re a crypto enthusiast with a drive to learn and lead within a highly innovative environment, this role is for you.

What You’ll Work On

• Operate and scale production-grade blockchain infrastructure, running full nodes across chains like Arc, Ethereum, Solana, Base, and more.
• Design, build, and maintain Kubernetes clusters with a focus on high availability, security, and self-healing workloads.
• Support multiple engineering teams through automation-first CI/CD pipelines, enhancing build quality and velocity.
• Develop infrastructure using Infrastructure-as-Code (IaC) tools such as Terraform to manage cloud-native deployments.
• Integrate AI-assisted developer tools (e.g., Cursor, agentic workflows) to streamline reliability engineering workflows and decision-making.
• Participate in a follow-the-sun on-call rotation covering business hours and 24/7 production support, driving incident response and postmortems.
• Partner with security teams to ensure strong security postures across production environments.
• Lead and/or mentor team members by sharing best practices and guiding architectural decisions.

What You’ll Bring To Circle (not All Required)

• 4+ years of experience in SRE, DevOps, or Infrastructure Engineering, ideally within a cloud-native or blockchain environment.
• Demonstrated experience operating and debugging blockchain nodes and distributed systems.
• Solid experience administering and developing on Kubernetes, including Helm charts, controllers, operators, RBAC, and observability.
• Experience with CI/CD pipelines, container image builds, and deployment strategies like blue-green and canary.
• Proficiency with coding and/or scripting with the following languages (Go, Python, Shell).
• Hands-on with public cloud providers, especially AWS and/or GCP.
• Strong grasp of SQL databases, schema design, and stateful services in production.
• Familiarity with AI-assisted development tools or experience exploring agentic workflows in infrastructure contexts is a big plus.
• Critical thinker with a strong sense of ownership and the ability to make decisions independently in ambiguous situations.
• Excellent communication skills for cross-functional collaboration.
• Experience with interacting with smart contracts.
• Genuine passion for crypto and blockchain infrastructure.

Staff Site Reliability Engineer (IV)

• All the requirements of a Senior Site Reliability Engineer and:
• 6+ years of experience in SRE, DevOps, or Infrastructure Engineering, ideally within a cloud-native or blockchain environment.
• Proven track record of technical leadership in complex, distributed systems architecture and design.
• Deep expertise in blockchain protocols and their infrastructure demands.
• Kubernetes internals and tuning for large-scale workloads.
• Agentic automation strategies and applying AI tooling in real-world engineering workflows.
• Observability and chaos engineering techniques to stress-test reliability.
• Experience mentoring engineers and scaling SRE best practices across teams.
• Strong opinions on code quality, testing strategy, and automation culture.

Circle is on a mission to create an inclusive financial future, with transparency at our core. We consider a wide variety of elements when crafting our compensation ranges and total compensation packages. Starting pay is determined by various factors, including but not limited to: relevant experience, skill set, qualifications, and other business and organizational needs. Please note that compensation ranges may differ for candidates in other locations.

We are an equal opportunity employer and value diversity at Circle. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status. Additionally, Circle participates in the E-Verify Program in certain locations, as required by law. Should you require accommodations or assistance in our interview process because of a disability, please reach out to accommodations@circle.com for support. We respect your privacy and will connect with you separately from our interview process to accommodate your needs.