Software Engineer II, Infrastructure Security

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.

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

• 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

• 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

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

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’re Klaviyo (pronounced clay-vee-oh). We empower creators to own their destiny by making first-party data accessible and actionable like never before. We see limitless potential for the technology we’re developing to nurture personalized experiences in ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators—ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you’re ready to do the best work of your career, where you’ll be welcomed as your whole self from day one and supported with generous benefits, we hope you’ll join us.

AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human-in-the-loop). We provide accommodations as needed. 

By participating in Klaviyo’s interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice.

Klaviyo is committed to a policy of equal opportunity and non-discrimination. We do not discriminate on the basis of race, ethnicity, citizenship, national origin, color, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law.