Senior Software Engineer, Web Platform

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 the Web Platform Team
The Web Platform team owns all the ways we build, ship, monitor, and test frontend code at Klaviyo. As a Senior Software Engineer on the team, you will be deeply involved in how we build, maintain, and improve our deployment processes, core frontend services, and overall frontend performance.
You can look forward to being a part of a highly technical team with significant domain expertise. We oversee a well organized monorepo that is leveraged across the organization that deploys 50+ times a day. The team also owns and orchestrates a GraphQL backend for frontend service to offer strong end-to-end typing across our stack.
As we look toward the next 6-12 months, we aim to focus on improved developer velocity through improved static analysis and CI structure as well as better platform web vitals by overhauling our application initialization process.
How You Will Make a Difference:

• You will collaborate closely with other Web Platform team members to help build a best in class platform for our end customers and engineers.
• You will be responsible for implementing new functionality into complex frontend systems.
• You will help ensure our frontend is stable and secure by keeping core dependencies (eg. React) up to date.
• You will help educate other Klaviyo engineers on frontend best practices by attending RFCs, reviewing PRs, and holding office hours.
• You will be an active participant in all team processes including standups, groomings, retros, on call, and more.
• You will help interview new engineering team members as we continue to grow our organization.

Who You Are:

• Experienced at building and maintaining platform tooling at a SaaS company. Ideally in the frontend platform space.
• Several years of professional experience with React and TypeScript.
• You have experience working on a JS build pipeline using tools like Webpack and Babel (or any of the various alternatives).
• Thrives in a fast paced, customer focused, and strategic environment.
• You have mentored other engineers before.
• You have been involved in large cross team technical projects before.
• Constantly thinking about frontend performance. If shaving kilobytes off a JS bundle or fixing wasted renders sounds appealing, we want to hear from you.

Technologies we use (not exhaustive):

• React, TypeScript, JavaScript, HTML, CSS
• Babel, Webpack, Eslint, Prettier
• REST, GraphQL, JSON Schema, and JSON:API
• CDNs (Fastly, Cloudflare)
• BuildKite
• Python, Django, Celery
• MySQL, Redis, Pulsar

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.