Team OverviewThe 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 impactAs 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 KlaviyoOwn meaningful components and services end to end, from implementation through production operationImprove the availability, scalability, latency, and efficiency of infrastructure security systemsCollaborate with senior engineers on system design and architecture, contributing ideas and technical solutionsIdentify performance, reliability, and security issues in distributed systems and drive improvementsWork extensively with technologies such as Python, Golang, AWS, Kubernetes, Terraform, and modern data storesParticipate actively in design reviews, code reviews, and whiteboarding sessionsContribute to operational excellence through monitoring, alerting, and incident responseParticipate in an on-call rotation with a focus on learning, prevention, and reducing operational toilBuild tooling, automation, and documentation that improve developer experience and security posturePartner with product-facing and platform engineers to ship impactful, secure solutionsWho you areYou have solid experience building and operating cloud-native, distributed systems in productionYou are comfortable writing production-quality code in a language such as Python or GoYou have hands-on experience with AWS (or a similar cloud provider) and understand managed services, networking, and IAM conceptsYou have experience working with containers and orchestration platforms such as KubernetesYou are comfortable owning services and features independently, while knowing when to ask for feedback or supportYou understand the fundamentals of scalable, multi-tenant architectures and secure system designYou care about reliability, performance, observability, and security—not just shipping featuresYou are comfortable participating in on-call and responding to production issuesYou communicate clearly, collaborate well, and enjoy working through technical problems as a teamYou regularly use modern developer tooling, including AI-powered tools, to improve productivity and code qualityNice to haveExperience building or integrating security-focused systems (e.g. secrets management, IAM, authn/z, policy enforcement)Familiarity with service meshes, API gateways, or zero-trust architecturesExperience improving performance in distributed systems or debugging complex multi-service workflowsTech StackKlaviyo'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 / FastAPIMySQL / Redis / MemcachedRabbitMQ / Celery / Apache Kafka / Apache PulsarAWS / Terraform / KubernetesLocation & Work ModelThis 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 here