Senior Software Engineer - Full Stack/Frontend

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 Klaviyo
At Klaviyo, stepping into a Senior Software Engineering role means immersing yourself in high-visibility, high-impact projects that resonate deeply with our users. In this role, you will be a key player on our team, directly shaping our product experience to ensure it is intuitive and engaging for a diverse customer base.
You'll have the opportunity to work alongside a team of committed and skilled engineers who are not just passionate about technology but are pioneers in creating seamless user experiences. By joining us, you'll engage in meaningful work that directly enhances how businesses connect with their customers.
Klaviyo is a place for growth and learning and you'll have ample opportunities to expand your technical and collaborative skills, owning major features from conception to deployment. Our environment promotes continuous learning, offering you the chance to enhance your expertise across various domains and technologies.
How you will make an impact

• Building User-Focused Features: Develop and maintain highly visible, user-facing features that enhance the intuitiveness and delightfulness of using Klaviyo. Use advanced frontend technologies to create scalable, efficient, and visually compelling user interfaces that directly address customer needs.
• Engineering Best Practices: Contribute significantly to the engineering culture at Klaviyo by establishing, documenting, and promoting best practices. Lead initiatives to introduce and standardize frontend frameworks and tools that increase development efficiency and maintainability.
• Web and Browser Performance Expertise: Ensure optimal performance of our web applications, focusing on enhancing responsiveness and efficient browser rendering to deliver a seamless user experience. You'll leverage tools like Sentry and browser devtools to monitor, debug, and address performance concerns.
• Team Collaboration and Mentorship: Engage actively in building a strong team environment centered on education and mentorship. Learn alongside your peers to continuously advance collective skills and enhance software quality.

Who you are

• Experienced Frontend Leader: You bring extensive professional experience in leading frontend development projects, with expert proficiency in React and other modern JavaScript frameworks. You have a strong grasp of state management libraries, caching strategies, RESTful APIs, Apollo GraphQL, and UI testing tools like Cypress, Puppeteer, or Playwright.
• Architecture and Design Acumen: Demonstrable ability to architect robust, scalable frontend systems. You can effectively break down and prioritize tasks, design reusable and modular components, and foresee potential challenges in large-scale implementations. You thrive in a collaborative environment, working very closely with our design and user research team to translate wireframes and designs into functional requirements.
• Customer-Oriented Developer: Committed to creating user-centric solutions, you'll leverage our user research teams, A/B testing framework, and UX design principles to refine product features for maximum impact and usability.
• Eager Learner and Team Player: Your drive to stay ahead of technology trends is matched by your enthusiasm for sharing knowledge. You actively seek out opportunities to enhance both your technical and leadership skills within a dynamic team environment.
• Advocate for Quality and Precision: Known for a meticulous approach to development, you ensure that all features meet high standards of quality and performance before deployment. You lead by example in writing clean, testable, and efficient code.
• Mentorship and Guidance: While this is not a management role, you'll have a track record in mentoring, you are adept at coaching less experienced engineers, providing them with career guidance and technical advice. You are a go-to person for code reviews, offering insightful and actionable feedback.

Technologies we use

• Frontend Technologies: React, TypeScript, Redux, GraphQL
• Backend Technologies: Python, Django
• Databases and Messaging: MySQL, Apache Pulsar, Kafka, Clickhouse, Redis
• Infrastructure and DevOps: AWS, Kubernetes, Docker, Terraform

The pay range for this role is listed below. Sales roles are also eligible for variable compensation and hourly non-exempt roles are eligible for overtime in accordance with applicable law. This role is eligible for benefits, including: medical, dental and vision coverage, health savings accounts, flexible spending accounts, 401(k), flexible paid time off and company-paid holidays and a culture of learning that includes a learning allowance and access to a professional coaching service for all employees.
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.