Senior Software Engineer - Asynchronous Processing

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.

Klaviyo is growing fast and we have openings for all skill levels across all of our teams. Learn more about our engineering culture at https://klaviyo.tech

This role will be part of our Site Reliability Engineering (SRE) Team. SRE is what you get when you treat system operations as a software engineering problem. The mission of the Site Reliability Engineering team is to provide services, tooling, and guidance to Klaviyo's product engineers to make them more productive and ensure their services are sufficiently reliable, scalable, and secure. 

For the the Asynchronous Processing Team: Our most active current project is building an async platform for Klaviyo's various async workloads on Apache Pulsar. Klaviyo is mainly a python shop, so a lot of it involves building client libraries for our internal users in python, along with operating the actual Pulsar cluster.

The SRE team builds foundational backend services as well as tooling and automation to allow product teams to release and scale their software reliably and predictably. SREs are team players who work collaboratively amongst themselves and with engineers from product teams to build the platform Klaviyo relies on to power its products.

You you will own multiple foundational Klaviyo services and make a big impact on the productivity of our product engineering teams.

How you will make a difference:

• Ship foundational services to enable Klaviyo engineering to move faster with confidence
• Design and develop systems and processes that enable highly available & scalable systems
• Design, build and deliver software to dramatically improve the availability, scalability, latency, and efficiency of Klaviyo’s services
• Achieve break-throughs in systems throughput by identifying and eliminating bottlenecks
• Leverage technology such as Python, Go, Bash, Django, AWS, Kubernetes, Terraform, MySQL, Apache Pulsar, Redis, and Clickhouse to advance Klaviyo’s platform
• Champion best practices by actively collaborating with other teams in a culture that values technical design review
• Contribute to the company as a subject matter expert in multiple areas, constantly pushing yourself to be a better engineer and to level up all of your peers within your team and within Klaviyo.
• Mentor and pair with other Klaviyo engineers to build better software by focusing on performance, self-healing system, configuration as code; defensive programming, application security, etc.
• Participate in periodic on call duties with a focus on solving issues when they are discovered, preventing recurrences and minimizing alert fatigue 
• Work hand-in-hand with product-facing engineers to ship impactful code
• Perform quantitative analysis to understand and scale Klaviyo systems and manage the cross-functional effort to resolve scalability issues
• Produce and advocate for preventative, upstream solutions with internal stakeholders and external vendors and dependencies
• Confidently make informed, data-driven decisions in a fast paced environment with competing priorities
• Evangelize Site Reliability best practices across the engineering organization and community

Who You Are:

• BA or BS Degree in Computer Science, related field, or equivalent experience
• 5+ years of responsibility operating & scaling complex distributed systems
• Experience developing applications in Python, Ruby, Go, etc.
• Experience working on an engineering team building software
• Fundamental understanding of Linux (we run Ubuntu) and all layers of the networking stack; you should be confident administering and debugging production Linux systems
• Ability to handle yourself and complex systems in outage situations and to drive failures to root cause analysis and prevention of future issues

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. Please visit Klaviyo Rewards to find out more about our Total Rewards package.

Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process.

Base Pay Range For US Locations:$152,000—$228,000 USD

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.

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.

IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls.   By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice.  If you do not wish for Klaviyo to process your Personal Data, please do not submit an application.  You can find our Job Applicant Privacy Notice here and here (FR).