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Senior Software Engineer - Internationalisation

  • London, UK
  • Engineering

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.

Klaviyo is growing by leaps and bounds; as a result, we’ve recently established our Internationalisation team!

The Internationalisation team focuses on enabling every engineer at Klaviyo to write, test, and deploy frontend code as efficiently and easily as possible. While other teams are focused on shipping specific product features to Klaviyo customers, we focus on the underlying infrastructure they use and frontend problems that impact Klaviyo as a whole.

This particular position is an opportunity to help establish the foundation for how we will internationalise our product. 

We are looking to learn from you and leverage your past experience contributing to the internationalisation of a complex SaaS product in a multi team environment.

How you will make a difference:

  • Help design, build, and maintain a robust frontend system to make internationalisation integrated throughout the software development lifecycle. The code you write will help empower an organisation of 300+ engineers (and counting) ship frontend changes faster and more safely.
  • Mentor the engineering team at large on how to write frontend code effectively, with a focus on internationalisation patterns.

Who You Are:

  • An experienced engineer who has developed in and expanded on an internationalised complex SaaS product using React.
  • 2+ years of professional experience with React.
  • Strong knowledge of vanilla JS, ES2015+ syntax, and the Javascript ecosystem as a whole.
  • Familiar with HTML, CSS, and general web best practices.
  • Comfortable working across different parts of a large codebase.
  • Highly collaborative and communicative.
  • Authorisation to work in the UK without restriction.

Bonus points for:

  • Experience with Typescript.
  • Experience with custom frontend build systems + tooling (e.g. Webpack, Babel, TypeScript, ESLint, Jest, Jenkins, CDNs, etc.).
  • Developing application APIs (e.g. REST, GraphQL, JSON Schema, or JSON:API, etc).
  • Having established best practices in how a company writes, tests, and deploys frontend code.
  • Constantly thinking about frontend performance. If shaving kilobytes off a JS bundle or fixing wasted renders sounds appealing, we want to hear from you.

Klaviyo in EMEA;

London was our first non-US location for Klaviyo, opening up in 2019 and growing since then to a large team of people with teams across Sales, Customer Success, Marketing, Services, Partnerships, IT and HR. Collectively in EMEA we are contributing a significant part of Klaviyo’s overall global success, growth to date and opportunity that lies ahead. The good news is that we are still at a stage where everyone coming into the business has the opportunity to make a real tangible impact that you will be able to see and feel.

We are proud of everything we have built here in EMEA, a vibrant diverse team embracing hybrid working in line with the way the world of work has changed. When Klaviyos do travel to the office you’ll be able to use your monthly commuter allowance if you need it. Once here you'll be able to enjoy the comforts of an incredible environment with all the perks we love and you’d expect such as, free snacks / drinks, a peloton studio and a roof terrace overlooking the city to rival anything you’d find in London as well as regular team celebrations and company lunches.

As part of the Klaviyo team you will be looked after with some great benefits locally in EMEA including equity for all, private health cover for you and discounted for your household, financial and professional coaching, a generous annual learning allowance (£2.5k), 22 weeks full pay primary care giver leave (16 week secondary) and free books (yes, any books!) to name a few.

Get to Know Klaviyo

Klaviyo is a world-leading marketing automation platform dedicated to accelerating revenue and customer connection for online businesses. Klaviyo makes it easy to store, access, analyze and use transactional and behavioral data to power highly-targeted customer and prospect communications. The company's hybrid customer-data and marketing-platform model allows companies to grow by fostering direct relationships with customers, without giving up their valuable data to popular big-tech ad platforms. Over 265,000 innovative companies like Unilever, Custom Ink, Living Proof and Huckberry sell more with Klaviyo. Learn more at .

If you are a California, Colorado, Rhode Island, Washington, New York City, or Jersey City resident and this role is a remote role, you can receive additional information about the compensation and benefits for this role, which we will provide upon request. Requests can be submitted here . Additional information regarding benefits can be found at .

Klaviyo is committed to diversity and to a policy of equal employment opportunity and non-discrimination. We do not discriminate on the basis of race, color, religion, national origin, age, sex, marital status, ancestry, physical or mental disability, veteran status, gender identity, sexual orientation or any other characteristic protected by applicable law.

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