Senior Software Engineer - Amplify C.S

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace. We believe everyone deserves a fair shot at success and appreciate experiences beyond traditional job requirements. This role is for a Senior Software Engineer on Amplify, focused on building internal tools, platforms, and AI-powered automation that help Klaviyos work more efficiently and at scale. The work is highly visible and has a direct impact on how thousands of Klaviyos get their work done every day.

The Amplify Engineering team builds internal tools, platforms, and AI-powered automation that help Klaviyos work more efficiently and at scale as the company grows. We partner across Sales, Marketing, Engineering & Product, Customer Service & Success, and Finance to solve real operational problems with practical software. Our work spans internal applications, 3rd-party integrations, dashboards, CMS integrations, and robust AI systems that surface the right information at the right time to help teams make better decisions.

Location: Dublin, Ireland; hybrid model. Klaviyo supports work authorization and relocation for this position.

• Design, build, and own complex internal products and platforms, including internal web applications, APIs, data and event pipelines, and AI-powered workflows used daily by Sales, Marketing, Customer Service & Success, R&D, and Finance teams.
• Lead the end-to-end lifecycle of projects and features – from discovery and technical design through implementation, rollout, and long-term ownership.
• Partner closely with internal customers to understand their workflows and constraints, and translate real operational challenges into scalable, maintainable solutions that measurably improve productivity, quality, and reliability.
• Take ownership of the technical and architectural evolution of parts of the Amplify platform, anticipating scalability, reliability, and observability needs as usage grows.
• Define and maintain operational standards for the systems you own, including SLOs, monitoring, incident response, and follow-up on root-cause analysis.
• Use modern AI tools as part of your day-to-day engineering workflow (e.g. LLM-based tooling for design, coding, testing, and documentation), and help shape best practices for how the team applies AI responsibly and effectively.
• Contribute to shared patterns, tooling, and processes that make it easier for teams across Klaviyo to build high-quality internal tools and AI-powered systems consistently.
• Mentor and support other engineers through design reviews, pairing, and constructive feedback, leaving the codebase and systems better than you found them.
• Collaborate closely with Product, Design, Data, and operational partners to define requirements, trade-offs, and success metrics, ensuring Amplify’s work focuses on the highest-value problems.

• You care deeply about building software for the long term, balancing technical quality, delivery pace, and business impact.
• You have strong hands-on experience building and operating highly available, full-stack SaaS systems, and are comfortable owning complex problems end to end.
• You’ve led the delivery of significant projects or features independently, including discovery, technical design, implementation, rollout, and ongoing maintenance, and you’re comfortable providing technical direction to others.
• You have deep expertise in one or more areas of modern web engineering (e.g. backend services, data pipelines, internal platforms, or AI-enabled systems) and a solid understanding of scalable, multi-tenant architectures.
• You regularly use AI-powered tools in your development workflow and are curious about applying AI thoughtfully to improve engineering productivity and system capabilities.
• You take ownership of operational excellence for the systems you build, including performance, reliability, observability, and on-call participation where required.
• You enjoy questioning convention and continuously improving how things work, whether that’s architecture, tooling, workflows, or team practices.
• You are a clear communicator and collaborative teammate, comfortable leading technical discussions, writing design docs or RFCs, and keeping stakeholders aligned.
• You enjoy working in small, autonomous, agile teams, shipping incrementally, and partnering closely with product managers and other engineers to deliver better outcomes.

• Experience building internal tools, platforms, or automations for developers and/or non-technical stakeholders, with a track record of improving reliability, productivity, or operational efficiency.
• Hands-on experience in full-stack environments, including diagnosing and improving application performance, database queries, and complex, multi-service workflows.
• Practical experience building or integrating AI-powered systems and agents; e.g., workflows using LLM APIs/SDKs, agentic or automated workflows, RAG pipelines, or evaluation/monitoring frameworks.
• Experience working with cloud infrastructure (AWS preferred), infrastructure-as-code (Terraform), and containerised environments (Kubernetes), and designing services that run reliably at scale.

Klaviyo’s platform is primarily built with Python and React and runs on AWS. Core technologies include:

• Python / Django / FastAPI
• Typescript / React
• 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 value ownership, continuous learning, and collaboration. We are committed to building inclusive teams and encourage applications from candidates of all backgrounds.

We are growing fast and have openings for all skill levels across all teams. Learn more about our engineering culture at : Base pay range in local currency: €92,000—€138,000 EUR. Our total compensation may include bonuses, equity, and benefits; details provided during hiring.

AI fluency at Klaviyo includes responsible use of AI. We provide accommodations as needed. By participating in Klaviyo’s interview process, you acknowledge you have read and will adhere to our Guidelines for using AI in the Klaviyo interview Process. xcfaprz

Equal opportunity: Klaviyo is committed to a policy of equal opportunity and non-discrimination.