Senior Software Engineer, Agent Platform

Senior Software Engineer, Agent Platform

Engineering Boston, MA

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.

As a Senior Software Engineer, Agent Platform
, you’ll play a key role in designing and scaling the backend systems that power our AI products and agent solutions. This backend-heavy role gives you opportunities to influence architecture, async processing, and distributed systems. You’ll collaborate closely with product managers, ML engineers, and data scientists to deliver real-world impact at scale.

How you ll make a difference:

• Design and build backend systems to scale AI solutions for 167K+ customers.
• Contribute to our agentic architecture to support performant AI agents.
• Build tools to tune LLM-based features, deploy agents, MCP and RAG in production, and evaluate performance using tools like Arize, OpenAI, Bedrock, Lang Chain, vLLM and Ray.
• Develop reliable, scalable data pipelines and APIs for AI systems.
• Foster a culture of ownership, experimentation, and customer-first thinking.

Who You Are:

We encourage candidates to apply even if they do not meet all the qualifications listed. AI Ops is a rapidly evolving space and we are all constantly learning!

• 5+ years of experience as a backend software engineer, building scalable, distributed systems.
• Strong experience working in production environments and launching ML/AI projects.
• Hands-on experience with generative AI and agentic AI applications in production.
• Proficient in Python (or similar).
• Comfortable collaborating with cross-functional technical partners.
• Curious, proactive, and eager to learn.

Nice to Have:

• Experience with big data tools (e.g., Apache Spark, Ray).
• Familiarity with cloud infrastructure (AWS, Terraform, Kubernetes).
• Knowledge of ML frameworks (Huggingface, PyTorch, Tensor Flow, Keras).

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

Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.

Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant’s job-related skills, relevant experience, education or training, and work location.

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.

Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process.

Base Pay Range For US Locations: $148,000 — $222,000 USD

This role may require up to 10% travel for purposes such as new hire onboarding, client or partner work if applicable, team meetings, and industry events. Travel is coordinated in advance.

Get to Know Klaviyo

We’re Klaviyo…