AI Engineer Intern (Summer 2026)

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.

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 167,000 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.

About our Internship

At Klaviyo, our Engineering team builds the foundational technologies that power how brands grow through owned marketing. As an AI Engineering Intern 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 data scientists, 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 internship 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.

Interns come 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.

How You’ll Make a Difference

• Design and build backend systems that support scaling our AI solutions for 167K+ 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.
• Transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up.

Who you are:

Pursuing an advanced degree Phd preferred in Computer Science, Artificial Intelligence, Machine Learning, or a related field, Graduating in December 2026 or May/June 2027

• 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.
• You’ve already experimented with AI in work or personal projects, and you’re excited to dive in and learn fast. You’re hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient. 

Nice to Have

• 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

Internship Logistics

• Our Summer Internship Program is an 11-week [June 1 - August 14] paid experience at our Boston, MA headquarters. Interns are required to be in office 5 days a week.
• Before diving into individual teams and projects, all interns will complete Klaviyo Base Camp - our customized onboarding experience. Base Camp provides focused time to learn about Klaviyo, our product, the ins and outs of engineering and spend time getting to know other interns. This robust training experience ensures all interns join their teams fully prepared to dive into project work and make an immediate impact. 
• Our Boston office is fun - our interns stay fueled with free snacks and drinks, take breaks with each other over a game of ping pong, Nintendo, or a round of golf with our simulator, and relax in our speakeasy (yes you read that right!).
• Throughout the summer, Klaviyo interns attend social events to promote interaction beyond team and project work. In past years these events have included a Red Sox game, outings to Versus and Flight Club in the Boston Seaport, ice cream socials, and Ask Me Anything sessions with Klaviyo senior leadership.
• It is highly recommended that you apply prior to October 11 as we interview and hire on a rolling basis 

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

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. 

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.