Software Engineer II - SMS International

Posted Yesterday
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London, Greater London, England, GBR
Hybrid
68K-102K Annually
Mid level
Consumer Web • eCommerce • Marketing Tech • Retail • Software • Analytics • Generative AI
Best place for ambitious people to learn and grow.
The Role
Build and scale full-stack services supporting international SMS expansion and RCS capabilities. Design new services, work across monolithic and microservices architectures, optimize databases and application performance, develop CI/CD pipelines, debug production issues, and collaborate across teams. The role involves Python, Django, Go, React, AWS, distributed systems, and modern DevOps tooling, with a focus on reliable mobile messaging products for global customers.
Summary Generated by Built In

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.

About the Team

This role is for the SMS International team that is part of Mobile Platforms. 

The Mobile Platforms team at Klaviyo is responsible for empowering the over 200,000 Ecommerce clients we work with on a global scale to deliver effective experiences on mobile devices. This team focuses on performance optimization and continuous development of our Mobile Marketing Channels (SMS, Push Notifications, In App Messages, WhatsApp and RCS), Mobile SDKs (iOS, Android and React Native). While Email was how Klaviyo began, Mobile messaging is truly the way of the future.

The SMS International team within Mobile Platforms is responsible for the expansion of SMS capabilities into new countries and regions and is also spearheading the development of RCS as a new capability to be offered to customers alongside existing channels. We have an ambitious roadmap for 2026 and 2027 that puts the team at the heart of the company’s objectives and it is an exciting time to join the team!

About the Role

As a Fullstack Software Engineer II joining the SMS International team you will be working with a team of 4 other colleagues to deliver RCS and SMS International expansion to meet the company’s objectives. You will get the chance to build brand new services, understand how they fit into the bigger picture and plan how to architect and scale them successfully to serve our customers. 

Technologies we use (not exhaustive):

  • Claude Code, with other LLM tools also available
  • Python, Django, Go, React, RabbitMQ, Celery, MySQL, DynamoDB, Elasticache, Redis
  • Amazon Web Services (EC2, RDS, Aurora, SQS etc.), Terraform, Kubernetes, Splunk, Buildkite, Grafana, and other modern DevOps tools

What we are looking for

  • 3-5 years of experience in a software engineering discipline
  • Experience with full stack application development
  • Experience working with both monolithic and microservices architectures
  • Experience working with AI tools to deliver business outcomes
  • Experience with database design that can withstand high query volumes
  • Experience with CI/CD pipelines
  • Experience debugging performance issues and improving application performance
  • An interest and aptitude for collaboration across teams and disciplines

Nice to Have

  • Experience creating new services with scalability in mind. Exposure to large-scale system design
  • Experience with AWS or any similar cloud provider
  • Communication domain experience

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:
£68,000—£102,000 GBP

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).
 

Skills Required

  • 3-5 years of experience in a software engineering discipline
  • Experience with full-stack application development
  • Experience working with both monolithic and microservices architectures
  • Experience working with AI tools to deliver business outcomes
  • Experience with database design that can withstand high query volumes
  • Experience with CI/CD pipelines
  • Experience debugging performance issues and improving application performance
  • Interest and aptitude for collaboration across teams and disciplines
  • Experience creating new services with scalability in mind
  • Exposure to large-scale system design
  • Experience with AWS or a similar cloud provider
  • Communication domain experience

What the Team is Saying

Amit
Eva
Tai
Mads
Uche
Ben
Risa
Kit
Angela
Laksh
Laksh
Devin
Anthoney Kelley
Carmel
Carmel
Andrew Bialecki
Mohamed Ali

Klaviyo Compensation & Benefits Highlights

How does Klaviyo ensure its pay and bonus plans are competitive?

Klaviyo supports competitive pay through a total rewards approach that combines salary, equity, bonus opportunities, benefits, learning support and a performance culture tied to measurable impact. 

  • Competitive total rewards: Klaviyo’s benefits overview highlights competitive salaries, 401(k) match, employee referral bonuses, equity, an employee stock purchase plan, flexible paid time off, commuter/transit support, fitness reimbursements, mental and emotional wellbeing programming and learning support. External reviews reinforce the value of the package, with employees citing competitive pay, bonuses, RSUs, ESPP, health insurance, parental leave, unlimited PTO and learning stipends as meaningful parts of the employee experience.
  • Pay connected to impact and outcomes: Klaviyo’s handbook frames performance around ownership, clarity and measurable results. The value “Know the score” states that results matter more than effort alone, while “Drivers wanted” emphasizes proactive ownership and “Be meticulous in your craft” reinforces a high bar for work quality. That creates a compensation and recognition philosophy where strong outcomes, not just activity, are central to advancement and rewards.
  • Equity and long-term value: Equity is a visible part of Klaviyo’s rewards story. Klaviyo offers equity packages to all full-time employees, vesting over four years, and provides an employee stock purchase plan. That ownership opportunity sits within a growing business: in Q1 2026, Klaviyo reported $358 million in revenue, up 28% year over year, and raised full-year 2026 revenue guidance to $1.514 billion to $1.522 billion. Those business results give employees a clear connection between company performance, long-term growth and the value of ownership-based compensation.
  • Rewards supported by growth and development benefits: Klaviyo’s compensation package is paired with benefits that help employees grow their careers and build long-term value. K-Pro Learn, learning stipends, mentorship, Career Architecture and manager development programs support continued skill-building. A customer success manager noted that Klaviyo offers a learning stipend for job-related coaching or training, while employee survey insights show 78% of respondents feel they are gaining the skills and experience to grow their careers.
  • External signals:
    • Compensation Sentiment: External reviews frequently praise Klaviyo’s competitive salary, bonuses, equity, RSUs, ESPP, 401(k) match, learning stipend and generous benefits. (Glassdoor; Comparably)
    • Rewards Ratings: Comparably rates Klaviyo’s compensation an A and perks and benefits an A. (Comparably)
    • Employee Value Signals: Reviews highlight PTO, health insurance, parental leave, office amenities, learning support and work-life balance as part of the overall rewards package. (Glassdoor; Comparably)

Bottom line: Klaviyo keeps compensation competitive by combining salary, bonus opportunities, equity, ESPP, retirement support, benefits and learning resources with a culture that rewards ownership, measurable outcomes and long-term impact.

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The Company
Boston, MA
2,400 Employees
Year Founded: 2012

What We Do

Klaviyo (NYSE: KVYO) is the B2C CRM. Powered by its built-in data platform and AI, Klaviyo combines marketing automation, analytics, and customer service into one unified solution, making it easy for businesses to know their customers and grow faster. Klaviyo (CLAY-vee-oh) helps over 183,000 brands like Mattel, Glossier, Daily Harvest, and Liquid Death deliver 1:1 experiences at scale, improve efficiency, and drive revenue.

Why Work With Us

We refer to our employees as ‘Klaviyos’, and we make up a diverse community united around shared values: We’re curious, collaborative, driven, innovative, fun, and fully ourselves at work. No matter which team you join, your work won’t just impact Klaviyo. It’ll help empower our customers and enable creators across the globe to own their destinies.

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Hybrid Workspace

Employees engage in a combination of remote and on-site work.

Typical time on-site: 3 days a week
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