Senior AI Engineer

Klaviyo is seeking a Senior AI Engineer to join its Customer Agent team in Boston, MA. This onsite role focuses on designing scalable backend systems and AI agent capabilities, collaborating with product managers, ML engineers, and data scientists to power production AI models at scale. The position offers a salary range of USD 148,000 - 222,000 per year and requires at least five years of professional software engineering experience.

Responsibilities

• Shape and implement backend architectures that scale Klaviyo's AI solutions to more than 167,000 customers.
• Create resilient data collection and processing pipelines to train and consume machine learning models.
• Build reliable services that deploy and serve AI models in production at scale.
• Help evolve the agentic architecture to improve autonomy and performance of AI agents.
• Foster a culture of ownership, experimentation, and customer-focused product development.

Requirements

• 5-7 years of professional software engineering experience, with a strong emphasis on backend systems and distributed architectures.
• Hands-on experience delivering generative and agentic AI applications in production, including prompt engineering, few-shot learning, fine tuning, and evaluation.
• Proven background as a backend engineer building scalable distributed systems that support AI agent capabilities.
• Proficiency in Python and modern backend frameworks (FastAPI or Django preferred).
• Experience designing and implementing human and automated evaluations to ensure AI model quality.
• Experience with big data tools such as Apache Spark and Hadoop.
• Extensive experience with asynchronous processing and distributed task queues (Celery, Kafka, SQS, RabbitMQ, Redis).
• Strong knowledge of databases and ORMs, including SQLAlchemy and Alembic.
• Familiarity with cloud-native architectures (AWS) and Kubernetes; capable of managing infrastructure and CI/CD pipelines.
• Adept at designing and building robust APIs.
• Ability to operate autonomously, handle ambiguity, and thrive in a fast-moving, startup-like environment.
• Curiosity-driven, with a commitment to staying current in this rapidly evolving field.
• Comfort working directly with product managers and customers to shape solutions.

Technologies

• Python
• FastAPI
• Django
• Apache Spark
• Hadoop
• Celery
• Kafka
• SQS
• RabbitMQ
• Redis
• SQLAlchemy
• Alembic
• AWS
• Kubernetes

Nice to have

• Experience training and deploying machine learning models in production with tangible business impact.
• Knowledge of reinforcement learning.