Senior Software Engineer - Channel Processing

Senior Software Engineer – Channel 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 klaviyo.com/careers to see how we empower creators to own their own destiny.

The Channel Processing team has direct technical responsibility for Klaviyo's most-used engagement product. It is responsible for designing, building and operating highly-scalable, highly-available distributed systems to process ever-increasing campaign traffic. Our systems are used by hundreds of thousands Klaviyo customers to schedule/process tens of thousands campaigns and deliver over 1B messages every day. Besides the daily high volume traffic, the more challenging task is to deal with super spiky volume at online sale seasons. During the 2025 Black Friday and Cyber Monday, over 10B messages got processed and delivered through our system without any manual intervention. We're proud of these achievements and passionate about continually scaling and evolving our systems to support and help drive Klaviyo's rapid growth by using modern technologies and patterns. Going beyond the established channels, this team is aiming to build a highly generic and extensible campaign platform to empower the new emerging message channels in future by leveraging our years of experience/expertise. If you like to take on new challenges working on large-scale, complex systems, come join us.

In this role, you will own and build features/services that hundreds of thousands of Klaviyo customers rely on daily to drive their business forward. Work on crafting our highly-scalable, highly-available campaign pipeline that processes and delivers hundreds of millions of messages daily growing to billions scale. Collaborate radically with teams and stakeholders across Klaviyo on designs, implementations, and engineering practices. Learn new technologies, bring them to the team and apply them to evolve our systems to the next level. Help us improve our experimentation and development processes, and mentor other engineers on the team. Participate in the technical interview process to help maintain a high bar for our growing teams. Contribute to the company as a subject matter expert, constantly pushing yourself to be a better engineer and to level up all of your peers within your team and within Klaviyo.

• Have 4-6+ years of experience in a software engineering discipline and have architected, built and delivered at least one complex system.
• Experience on large-scale system architecture, technologies and patterns. Have a good understanding of their pros/cons and use scenarios, able to apply them to system design by making appropriate tradeoffs to meet the business needs best.
• Love digging into performance and scalability issues to drive breakthrough solutions– whether it's a performance degradation or too many clicks in a workflow, a database query timing out, or a queue that just won't drain. You recognize all problems can be solved.
• Passionate about growing and improving a product daily using a data driven mindset, familiar with system monitoring and alerting techniques.
• Proven experience with being a coach and a mentor for team members and helping them grow.
• Like working on small, high-performing autonomous agile teams. At Klaviyo, you will have ownership of features, but you'll collaborate radically with everyone to make sure we produce the right solution.

Technologies we use (not exhaustive): Languages & Frameworks: Python, Django, React Data & Infrastructure: MySQL, Redis, Memcached, Apache Zookeeper, Apache Pulsar Cloud & DevOps: AWS (EC2, RDS, Aurora), Terraform, Jenkins

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.

Base Pay Range For US Locations: $148,000 — $222,000 USD

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.

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.

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.

You can find our Job Applicant Privacy Notice here and here (FR).