Senior Software Engineer, Reliability

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.

Senior Software Engineer, Reliability (Dublin)

Team Overview:

As a Senior Software Engineer, Reliability, you’ll ensure Klaviyo’s critical platforms are reliable, scalable, and sustainable while enabling rapid product development. We treat reliability as a core product feature and use software engineering to solve complex systems and operational challenges.

Our work spans security, infrastructure, and software development, requiring us to understand systems and engineering.  We build complex, foundational solutions that must be extremely reliable, secure, and performant at global scale.

Our charter is to build and operate foundational services and infrastructure, define clear reliability objectives, reduce operational toil through automation, and continuously improve systems based on real production learnings. The work is highly visible and directly impacts how Klaviyos build software and how customers experience Klaviyo every day.

How You’ll Make an Impact:

As a Senior Software Engineer, Reliability, you will build and operate the platforms, systems, and services that underpin Klaviyo’s reliability and operational excellence. You will:

• Build and operate foundational, security-critical services with a strong emphasis on availability, scalability, latency, and fault tolerance
• Apply software engineering principles to automate infrastructure, reduce operational toil, and improve system reliability at scale
• Design, implement, and evolve systems using SRE best practices
• Define and refine SLIs, SLOs, and error budgets to guide engineering decisions
• Improve observability, alerting, and incident response to reduce mean time to detection and recovery
• Participate in on-call rotations with a focus on sustainable operations and automatic remediations
• Perform quantitative analysis to understand system behavior, capacity constraints, and scaling limits
• Identify systemic risks and reliability bottlenecks and drive long-term, preventative solutions
• Collaborate closely with product, platform, and security engineers to influence architecture early and ship reliable systems
• Mentor and pair with other engineers, helping raise the bar for reliability, operational maturity, and engineering excellence

Who You Are:

You are a cloud-native, pla