Software Engineer II - SMS International

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 creat