Sr. Software Engineer, Messaging Infrastructure at Klaviyo – Dublin | Jobyssey

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 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. How You Will Make a Difference

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.

Who You Are

5+ years of professional software engineering experience building and operating production distributed systems.
Deep fluency in at least one backend language (Python, Go, Java, Scala, or similar) and comfort navigating large, complex codebases.
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.
Solid understanding of distributed systems fundamentals: consistency models, CAP, tradeoffs, idempotency, retries and backoff, rate limiting, and graceful degradation.
Ability to operate effectively in a high-ownership culture: you drive your work forward,unblock yourself, and hold yourself accountable to outcomes, not just effort.

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

Location & Work Model:

This role is based in Dublin, Ireland and follows a hybrid working model. Klaviyo supports work authorization and relocation for this position.

At Klaviyo, we enjoy tackling meaningful engineering challenges and value people who take ownership, learn continuously, and collaborate openly. We are committed to building inclusive teams and encourage applications from candidates of all backgrounds.

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

Our salary range reflects the cost of labour in the country where the job post is advertised. 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 in Local Currency:

€92.000—€138.000 EUR

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.

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).

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