Job Description
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.
About Klaviyo
Klaviyo is a leading marketing automation platform that helps businesses grow by delivering personalized experiences. Our mission is to empower creators to own their destiny. We believe in providing an exceptional developer experience that enables our engineering teams to build and ship high-quality software efficiently and with confidence.
About the Team
The Messaging Infra organization at Klaviyo is focused on high-growth customer engagement through various messaging channels (email SMS/MMS/RCS mobile push WhatsApp and more). We work with multiple stakeholders to provide best-in-class service and reliability to connect a wide range of businesses from entrepreneurs to enterprises with their end users. The messaging platform is a mission-critical system responsible for delivering billions of messages and must be architected for massive scale and reliability.
As a Senior Lead Software Engineer within the Messaging Infra organization you will serve as the primary technical architect for our high-volume message delivery systems while driving the overarching technical vision for channel expansion. You will partner with leaders across all channels to ensure a scalable reliable and performant platform strategy acting as a key technical liaison to the broader Mobile Channels and Messaging Infrastructure pillar. Your leadership will ensure that our core systems are not just maintained but architected to accelerate innovation and business impact while raising the bar on scalability and reliability.
What You'll Do
As a Senior Lead Software Engineer you will have an overarching responsibility for the architecture health and scaling of the Messaging Infra platform with a focus on high-volume message delivery. Your role will involve:
- Technical Strategy: Define the technical strategy and architectural vision for the Messaging Infra platform ensuring all system improvements align with long-term business goals for massive scalability high reliability and low latency message delivery.
- System Architecture and Improvement: Serve as the primary architect to build and improve high-volume message delivery systems across multiple channels focusing on throughput performance and reliability.
- Cohesive Technical Vision: Drive technical leadership to guide architectural decisions across multiple teams striving towards a cohesive technical vision across multiple roadmap items and providing solutions for complex problems around scalability and performance.
- Platform Rollouts and Product Execution: Oversee and execute the planning and seamless rollout of major software releases and updates for the platform managing the entire lifecycle from design to deployment in production environments including significant individual contributions.
- Problem Solving and Reliability: Act as a go-to expert for diagnosing and resolving complex performance scalability and reliability issues across the messaging platform. Implement proactive monitoring and telemetry to identify and address problems before they become critical incidents.
- Mentorship: Mentor other engineers regularly primarily experienced lead and senior engineers to develop new technical leadership for the company.
- Cross-functional Collaboration: Partner with product managers deliverability and compliance specialists and other stakeholders to gather requirements resolve conflicts and ensure alignment across all teams and projects.
- Continuous Improvement: Stay current with emerging technologies and industry trends evaluating new tools and practices to identify how they can improve systems and internal processes.
Who You Are
- 12 years of experience in software development strong knowledge of computer science fundamentals domain-driven design and extensive expertise in architectural patterns specifically within the domain of distributed systems.
- Have proven that you can build and scale complex distributed systems including solving problems in sustainable ways balancing pragmatic development with ideal architecture breaking through technical obstacles with vigor and leading teams through crises by working side by side with them in the trenches.
- BA or BS Degree in Computer Science related field or equivalent experience.
- Technical Expertise: Deep expertise in relevant programming languages (e.g. Python Go) and cloud platforms (AWS Azure GCP) containerization (Kubernetes Docker) and Infrastructure as Code (Terraform). You are particularly passionate and an expert in multiple stack areas with strong and opinionated experience with various technologies and know how to pick the right tool for any job.
- Technical Strategy: Demonstrated experience in contributing to the product and platform vision as well as defining the strategy within the broader scope of long-term organizational needs.
- Architectural Skills: Strong understanding of software architecture design patterns and system integration with the ability to define technical strategies and influence architectural decisions across multiple teams.
- Soft Skills: Exceptional problem-solving analytical leadership and communication skills with the ability to articulate complex technical concepts to both technical and non-technical audiences.
- AI Enthusiast: You’ve already experimented with AI in work or personal projects and you’re excited to dive in and learn fast. You’re hungry to responsibly explore new AI tools and workflows finding ways to make your work smarter and more efficiently.
Nice to Have
- Experience with the email and/or SMS ecosystem including understanding of channel-specific protocols and security specifications (e.g. DKIM DMARC SPF) and familiarity with key 3rd-party entities (like mailbox providers anti-abuse groups and telecoms) and compliance rules/best practices.
- Background in performance optimization and a passion for digging into performance and scalability issues to drive breakthrough solutions.
- Familiarity with complex data management for testing including large datasets and production-like data replication.
Our Tech Stack
- Python Django FastAPI Celery
- Apache Kafka Apache Pulsar RabbitMQ Spark Airflow and other tech from the big data stack
- MySQL PostgreSQL Clickhouse Cassandra Redis
- Typescript React Backbone.js HTML JavaScript Babel Jest Webpack
- Graphite statsd Chronosphere
- AWS (EC2 RDS Aurora etc.) Terraform Docker Kubernetes (EKS) Pantsbuild Argo and other modern DevOps tools
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
Massachusetts Applicants:
It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.
Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. 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.
This 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-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.
Top Skills
What the Team is Saying
What We Do
Klaviyo (NYSE: KVYO) is the B2C CRM. Powered by its built-in data platform and AI Klaviyo combines marketing automation analytics and customer service into one unified solution making it easy for businesses to know their customers and grow faster. Klaviyo (CLAY-vee-oh) helps over 183000 brands like Mattel Glossier Daily Harvest and Liquid Death deliver 1:1 experiences at scale improve efficiency and drive revenue.
Why Work With Us
We refer to our employees as ‘Klaviyos’ and we make up a diverse community united around shared values: We’re curious collaborative driven innovative fun and fully ourselves at work. No matter which team you join your work won’t just impact Klaviyo. It’ll help empower our customers and enable creators across the globe to own their destinies.
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Klaviyo Offices
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Employees engage in a combination of remote and on-site work.
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Date Posted
04/20/2026
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