Software Engineer - SMS International

Confirmed live in the last 24 hours

Klaviyo

London, UK

On-site

Posted March 31, 2026

Job Description

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.

Why you should join the SMS International team that is part of Mobile Platforms

The Mobile Platforms team at Klaviyo is responsible for empowering the over 150,000 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 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 5 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):

Python, Django, Go, React, SQS, Celery, MySQL, DynamoDB, Elasticache, Redis
Amazon Web Services (EC2, RDS, Aurora, etc.), Terraform, Kubernetes, Splunk, Buildkite, Grafana, Chronosphere 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 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

We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025.

Please see the independent bias audit report covering our use of Covey here

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

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