Senior AI Engineer

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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 have built the infrastructure that connects thousands of businesses to millions of consumer profiles and trillions of messages. We now have an opportunity to build state‑of‑the‑art AI and machine‑learning technologies to power our products and develop AI agents that can automatically create and execute marketing or customer experiences, strategies, and campaigns for any business.

• Design and build backend systems that support scaling our AI solutions for 167k+ customers.
• Develop robust, reliable, and scalable data collection and processing pipelines for training and consuming machine‑learning models.
• Develop 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.

• 5+ years of hands‑on experience building and deploying generative AI and agentic AI applications into production, with expertise in prompt engineering, few‑shot learning, fine‑tuning, and evaluation.
• Experienced backend engineer with a strong record of building scalable, distributed systems, especially for AI agent capabilities.
• Proficient in Python and modern backend frameworks (FastAPI, Django preferred).
• Experience creating human and automated evaluations to ensure high AI model quality.
• Proficient in big‑data tools such as Apache Spark and Hadoop.
• Deep experience with asynchronous processing and distributed task queues (Celery, Kafka, SQS, Rabbit
  
  MQ, Redis).
• Strong understanding of database technologies and ORMs (SQL Alchemy, Alembic).
• Comfortable with cloud‑native architectures (AWS) and container orchestration (Kubernetes); can manage infrastructure and CI/CD pipelines.
• Skilled at designing and building robust APIs.
• Able to operate with a high degree of autonomy, handle ambiguity, and thrive in a fast‑moving, startup‑like environment.
• Driven by curiosity and continuously learning about the rapidly evolving AI field.
• Comfortable collaborating directly with product managers and customers to shape solutions.

• Trained ML models in the past and deployed them in production systems to generate business impact.
• Experience in reinforcement learning.
• Contributions to open‑source AI frameworks.

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$152,000—$228,000 USD

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.

We’re Klaviyo. 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 e‑commerce and beyond. If you’re ready to do the best work of your career, you’ll be welcomed as your whole self from day one and supported with generous benefits.

AI fluency at Klaviyo includes responsible use of AI (including privacy, security, bias awareness, and human‑in‑the‑loop). We provide accommodations as needed.

By participating in Klaviyo’s interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview process. For more information about how we process your personal data, see our Job Applicant Privacy Notice.

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,…