Klaviyo is growing fast and we have openings for all skill levels across all of our teams. Learn more about our engineering culture at https://klaviyo.tech

We love tackling tough engineering problems and look for Lead Software Engineers who are passionate about architecting, building, owning & scaling features end to end from scratch and breaking through any obstacle or technical challenge in their way. We push each other to move out of our comfort zone, learn new technologies and work hard to ensure each day is better than the last.

Klaviyo operates a real-time data platform coded in Python built for massive scale on Amazon Web Services (AWS). Engineers come to Klaviyo with experience in a variety of languages and from a number of disciplines.

Technologies we use (not exhaustive):
Python, Django, Celery, Java
MySQL, Cassandra, RabbitMQ, Redis
HTML, JavaScript, LESS, Backbone.js, React
Amazon Web Services (EC2, RDS, Aurora, etc.)Terraform, Ansible, Packer, and other DevOps tools

How you will make a difference:

• Wholly own features that thousands of our customers rely on daily to reach 1,000,000,000+ of consumers to drive their business forward
• Think in systems and design architectural patterns, while acting as a technical guide to others during architecture design and improving existing architectural patterns to ensure they are performant and scalable.
• Work on crafting our highly scalable real-time data pipeline that processes billions of events monthly across data sets growing to petabyte scale
• Be empowered to own the mission, technical direction and operations of projects that have immediate impact
• Advance your technical skills in all facets ranging from front end web development and user experience to machine learning and massively parallelized data pipelines
• Contribute to the company as a subject matter expert in multiple areas, constantly pushing yourself to be a better engineer and to level up all of your peers within your team and within Klaviyo
• Participate in technical interview process to help maintain a high bar for our growing teams

Who You Are

• Have 7+ years of experience and have architected, built and delivered at least one complex system.
• Proven success creating direction and specifications for others
• Ability  to execute independently across a wide array of areas as well as mentor and level up others
• Experience setting  higher-level technical direction and process with the help of peers and senior management
• Have experience building products that matter and pushing yourself and your team to be better engineers and build a product with passionate advocates
• Enjoy working with new technologies ranging from the frontend to backend, and are particularly passionate and an expert in multiple stack areas. You show this by having strong and opinionated experience with various technologies and know how to pick the right tool for any job
• Love digging into performance and scalability issues to drive breakthrough solutions-- whether it’s a slow loading UI or too many clicks in a workflow, a database query timing out, or a queue that just won’t drain. You recognize all problems can be solved
• Able to work with others to proactively set project and feature requirement, including work timelines prioritization 
• Experience onboarding and mentoring new team members while facilitate a learning culture and an environment where they can enhance their own skills