Software Engineer II, Infrastructure Security

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you’re a close but not exact match with the description, we hope you’ll still consider applying. Want to learn more about life at Klaviyo? Visit klaviyo.com/careers to see how we empower creators to own their own destiny.Team Overview The Infrastructure Security team makes it simple and easy for engineers to make secure choices while developing world-class software at high speed. Security is built in by default—seamless and effortless—making engineers’ lives better and Klaviyo more secure. Our work sits at the intersection of security, infrastructure, and software engineering. We build cloud-native platforms and services that are reliable, secure, and performant at global scale, forming the foundation that Klaviyo engineers rely on every day. This role is for engineers who enjoy building modern distributed systems, care about security and reliability, and want to have real impact across a large engineering organization. How you’ll make an impact As a Software Engineer on the Infrastructure Security team, you will build and operate the systems that help Klaviyo engineers ship secure software with confidence. You will: Design, build, and maintain cloud-native security services used across Klaviyo Own meaningful components and services end to end, from implementation through production operation Improve the availability, scalability, latency, and efficiency of infrastructure security systems Collaborate with senior engineers on system design and architecture, contributing ideas and technical solutions Identify performance, reliability, and security issues in distributed systems and drive improvements Work extensively with technologies such as Python, Golang, AWS, Kubernetes, Terraform, and modern data stores Participate actively in design reviews, code reviews, and whiteboarding sessions Contribute to operational excellence through monitoring, alerting, and incident response Participate in an on-call rotation with a focus on learning, prevention, and reducing operational toil Build tooling, automation, and documentation that improve developer experience and security posture Partner with product-facing and platform engineers to ship impactful, secure solutions Who you are You have solid experience building and operating cloud-native, distributed systems in production You are comfortable writing production-quality code in a language such as Python or Go You have hands-on experience with AWS (or a similar cloud provider) and understand managed services, networking, and IAM concepts You have experience working with containers and orchestration platforms such as Kubernetes You are comfortable owning services and features independently, while knowing when to ask for feedback or support You understand the fundamentals of scalable, multi-tenant architectures and secure system design You care about reliability, performance, observability, and security—not just shipping features You are comfortable participating in on-call and responding to production issues You communicate clearly, collaborate well, and enjoy working through technical problems as a team You regularly use modern developer tooling, including AI-powered tools, to improve productivity and code quality Nice to have Experience building or integrating security-focused systems (e.g. secrets management, IAM, authn/z, policy enforcement) Familiarity with service meshes, API gateways, or zero-trust architectures Experience improving performance in distributed systems or debugging complex multi-service workflows Tech Stack Klaviyo’s platform is primarily built with Python and React and runs on AWS. Engineers join us from a wide range of technical backgrounds and are supported in learning our stack. Core technologies include: Python / Django / FastAPI MySQL / Redis / Memcached RabbitMQ / Celery / Apache Kafka / Apache Pulsar AWS / Terraform / Kubernetes Location & Work Model This role is based in Dublin, Ireland and follows a hybrid working model. Klaviyo supports work authorization and relocation for this position. At Klaviyo, we enjoy tackling meaningful engineering challenges and value people who take ownership, learn continuously, and collaborate openly. We are committed to building inclusive teams and encourage applications from candidates of all backgrounds. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025.Please see the independent bias audit report covering our use of Covey hereOur salary range reflects the cost of labour in the country where the job post is advertised. The base salary offered for this position is determined by several factors, including the applicant’s job-related skills, relevant experience, education or training, and work location. In addition to base salary, our total compensation package may include participation in the company’s annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility.  Your recruiter can provide more details about the specific salary/OTE  range for your preferred location during the hiring process.Base Pay Range in Local Currency:€76.000—€114.000 EURThis role may require up to 10% travel for purposes such as new hire onboarding, client or partner work if applicable, team meetings, and industry events. Travel is coordinated in advance. Get to Know Klaviyo We’re Klaviyo (pronounced clay-vee-o