Lead Software Engineer - Campaigns

Location: Boston Hybrid (3 days/week in office)

Lead Software Engineer – Campaigns Configuration

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 careers.klaviyo.com to see how we empower creators to own their own destiny.

Why You Should Join the Campaigns Configuration Team

The Campaigns Configuration team is building the foundation for how Klaviyo customers create, manage, schedule, and understand the performance of their marketing campaigns across channels. This team owns the core configuration and reporting experiences that power Klaviyo’s Campaigns product.

Campaigns are one of the most used parts of the Klaviyo application, relied on by hundreds of thousands of customers to send targeted messages (Email, SMS, Push Notifications, and more) that deepen their relationships with their own customers. By joining the Campaigns Configuration team, you will have a direct impact on over 170,000 brands that use Klaviyo every day.

The team owns an ambitious roadmap, including:

• A reimagined Campaigns experience built from the ground up


• A new Omnichannel Campaign experience allowing users to send campaigns on multiple channels


• Intelligent personalization and future channel expansion


• Refactoring Klaviyo’s system architecture through domain decomposition


• Re-architecting the Campaigns experience for performance, scalability, and reliability

As a Lead Software Engineer on this team, you’ll sit at the intersection of architecture, execution, and cross-team collaboration for one of Klaviyo’s flagship product areas.

About the Role

As a Lead Software Engineer, you are the technical leader and primary interface between the Campaigns Configuration team and the broader engineering organization. You will:

• Provide technical oversight and direction across a portfolio of projects


• Shape and execute on the forward-looking architecture for multiple Campaigns domains


• Partner closely with the Engineering Manager, Product, and Design on strategy, planning, and execution


• Work through influence and delegation to help the team deliver reliably and at a high bar of quality

You’ll spend your time balancing hands-on work (design docs, reviews, complex implementation) with guiding the team toward solid technical decisions, especially at our largest scales (including Black Friday / Cyber Monday, when we help customers send billions of messages).

How You Will Make a Difference

• Lead technical direction for Campaigns Configuration




• Provide technical oversight and direction for a portfolio of Campaigns projects, including new channels, personalization, and analytics.


• Formulate and drive a forward-looking technical vision that aligns with broader business and platform initiatives.



• Own architecture and domain evolution




• Be responsible for the technical and architectural evolution of multiple key Campaigns domains (e.g., configuration, scheduling, reporting).


• Drive domain decomposition, service boundaries, and data model design to improve scalability, performance, and operational excellence.



• Deliver high-quality, scalable features




• Lead the design and implementation of best-in-class web experiences using React and TypeScript, backed by REST and GraphQL APIs.


• Ensure backend systems are robust, observable, and performant, with an eye on peak traffic events.
  Scrutinize and reduce technical ambiguity and risk for upcoming projects through design reviews, technical spikes, and clear decision records.



• Create and improve engineering processes




• Work with the Engineering Manager to ensure team adherence to solid engineering practices (testing, observability, rollout strategies, incident response).


• Create, teach, and improve shared engineering processes and patterns that can be adopted by adjacent teams.


• Uplevel adjacent processes, technology, and people by sharing best practices and reusable solutions.



• Influence beyond your immediate team




• Act as the primary technical interface to other Campaigns and platform teams, ensuring cohesive end-to-end solutions.


• Regularly collaborate with technical leads in other areas to align on patterns, standards, and shared components.



• Mentor and grow others




• Guide other engineers through design feedback, pairing, and thoughtful code reviews.


• Help teammates break down complex initiatives into clear, incremental deliverables with predictable timelines.

Who You Are

• 7+ years of software engineering experience, including significant fullstack work


• Strong backend experience, with a track record of building and scaling services in production
  Hands-on experience with:




• Frontend: React, TypeScript, and modern state management patterns (e.g., Redux or equivalent)


• Backend: Python with Django, FastAPI (or equivalent web frameworks)


• APIs: RESTful and GraphQL APIs


• Data & performance: relational databases (e.g., MySQL/Postgres), query optimization, caching, and performance tuning



• Experience acting as a tech lead or lead engineer for a team or domain:




• You have driven technical vision and execution for a portfolio of projects.


• You’ve owned architecture in at least one significant product area.


• You’re comfortable saying "no" or "not yet" when it protects long-term health.



• Strong systems and product thinking:




• Skilled in system design, reusable component architecture, and scalable frontend platforms.


• Comfortable designing systems that operate reliably at large scale and high traffic.


• Able to translate product ideas into pragmatic, incremental technical plans.



• Collaborative and influential:




• You work through influence and delegation rather than just personal heroics.


• You communicate clearly with engineers, product managers, and designers.


• You proactively provide and receive feedback within your pillar and across teams.



• Growth-oriented:




• Proven track record delivering complex features in fast-paced, product-led environments.
  You’ve experimented with AI tools in work or personal projects, and you’re eager to learn how they can improve developer and customer experiences.

Experience with marketing automation, messaging platforms, or analytics-heavy products is a plus, but not required.

Technologies We Use

You don’t need to know all of these on day one, but familiarity with several is helpful:

• Frontend: React, TypeScript, Redux


• Backend: Python, Django, FastAPI


• Data & messaging: MySQL, Redis, RabbitMQ, Pulsar


• APIs: GraphQL, REST


• Infrastructure: AWS, Terraform, Kubernetes

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