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.
The UCM (Unified Communication Management) team sits at the core of how Klaviyo delivers messages to customers at massive scale. We own the systems responsible for sending, routing, and processing billions of messages across channels, making UCM a critical pillar of Klaviyo’s platform and customer experience. Our work directly impacts deliverability, reliability, and performance for some of the most business-critical workflows at Klaviyo.
As a Lead Software Engineer on the UCM team, you’ll lead a group of engineers building and operating high-throughput, distributed systems that power message delivery end-to-end. You’ll work deeply in a microservices-oriented architecture, designing resilient, scalable infrastructure that operates at global scale. This is a hands-on leadership role where you’ll contribute to system design, implementation, and technical strategy while mentoring engineers and setting the technical direction for the team.
This role offers a unique opportunity to lead one of Klaviyo’s most foundational platforms—the systems that every message flows through. Your work will shape how we scale globally, improve reliability and performance, and enable faster innovation across product teams. If you’re excited about solving complex distributed systems problems and leading a team at the heart of Klaviyo’s messaging ecosystem, UCM is the place to do it.
How You Will Make a Difference:- Lead a team of engineers building and evolving Klaviyo’s core messaging and communication platform
- Own message ingestion, routing, processing, and delivery pipelines that handle billions of messages at scale
- Build and operate highly available, distributed systems that support global traffic, reliability, and performance
- Contribute directly to system architecture and code, driving best practices in scalability, resilience, and operational excellence
- Collaborate closely with product, infrastructure, and partner teams to enable new channels, use cases, and platform capabilities
- Grow and mentor engineers while helping shape the future of Klaviyo’s messaging infrastructure
- Transform messaging workflows by putting AI at the center, enabling smarter routing, optimization, and operational decision-making from the ground up
- 8+ years of engineering experience with strong backend skills (Python or Go or Similar)
- Comfortable coding and reviewing complex systems — this is a hands-on role
- Skilled in system design and scaling infrastructure using AWS
- Experience building developer platforms or internal tooling is a strong plus
- Clear communicator and collaborative team player
- 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 efficient.
- Python, Go
- AWS, Terraform, Redis, MySQL
- KDS, MKS, Redshift
This is a hybrid role based in Boston, with 3 days in office and 2 days remote per week.
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.
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
Klaviyo Boston, Massachusetts, USA Office
We're in the heart of the Financial district with easy access to public transportation and a short walk from South Station. We also have hubs in Denver, London and Sydney.
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