AI Engineer I

At Klaviyo, we believe the future of software lies not in productivity tools for human users but in software that can run and optimize itself based on outcome or reward metrics. We’ve built the infrastructure and application that serve as the interface between businesses and consumers. We now have over 183,000 customers, billions of consumer profiles, and hundreds of billions of customer messages and follow-on conversion data. We have a big opportunity to build state-of-the-art AI and machine learning technologies at Klaviyo to power our products and develop AI agents that can automatically create and execute marketing or customer experiences, strategies, and campaigns for any business.

At Klaviyo, our Engineering team builds the foundational technologies that power how brands grow through owned marketing. As an AI Engineer at Klaviyo, you’ll play a key role in designing and building scalable backend systems and user experiences that power our AI products and AI agent solutions. You’ll partner closely with product managers, machine learning engineers, and software engineers, to drive real-world impact at scale. This is a backend-heavy role with opportunities to influence architecture, async processing pipelines, distributed systems, and more.

This is an opportunity to apply your generative AI and agentic AI application skills in a production environment. You’ll be embedded within one of our engineering teams and work on meaningful projects that help customers interact with powerful marketing tools, all while building a strong technical foundation and connections across Klaviyo.

Early career talent comes to Klaviyo with experience in a variety of technical skills, but they are all passionate about building, owning and scaling features end-to-end from scratch and breaking through any obstacle or technical challenge in their way. As an AI-first company you will be encouraged to use AI tools to support your work, accelerate learning, and succeed in your role.

• Design and build backend systems that support scaling our AI solutions for 183K+ customers.
• Develop robust, reliable and scalable services to serve AI models in production environments.
• Contribute to evolving our agentic architecture — making our AI agents more self-sufficient and performant.
• Contribute to a culture of ownership, experimentation, and customer-centric product thinking.
• Engage with internal stakeholders to understand their needs and resolve blockers.
• Stay abreast of emerging AI trends and technologies, identifying and leveraging opportunities for their application within Klaviyo’s ecosystem.
• Work with the team on project planning and defining achievements, identifying dependencies, and meeting business goals.

• Previous internship experience in AI, machine learning, or related fields, with a strong interest in building and deploying AI projects.
• Have hands-on experience building and deploying generative AI and agentic AI applications into production.
• Proficient in Python and modern backend frameworks (FastAPI, Django preferred).
• Experience creating human and automated evals to ensure high AI model quality.
• Able to thrive in a fast-moving, startup-like environment.

• Trained ML models in the past and deployed them in production systems to generate impact to businesses
• Experience in reinforcement learning
• Experience with large-scale data processing tools including Spark.
• Experience building large scale backend systems

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