Greenhouse ·
full-timeSenior Software Engineer, Agent Runtime & Customer Workflows
Klaviyo · Boston, MA
Klaviyo is a marketing automation and customer data platform that empowers businesses to manage consumer profiles and communications at scale. As a Senior Software Engineer for the Agent Runtime and Customer Workflows team, you will focus on building the backend infrastructure for the company's AI-native conversational platform. Your daily responsibilities involve designing scalable systems that allow AI agents to reason, retrieve context, and execute multi-step workflows on behalf of customers. You will tackle applied AI challenges such as retrieval-augmented generation, hallucination mitigation, and the implementation of hybrid approaches that combine deterministic logic with large language models. The role requires building robust asynchronous processing pipelines, maintaining production reliability through observability and guardrails, and collaborating with cross-functional teams to translate customer feedback into technical solutions. This position is well-suited for experienced backend engineers with 5-7 years of professional experience, specifically those who have successfully deployed generative or agentic AI applications into production environments. You should be proficient in Python, familiar with distributed systems and message brokers like Kafka or RabbitMQ, and comfortable navigating cloud-native architectures to solve complex, high-volume data problems.
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. Want to learn more about life at Klaviyo? Visit klaviyo.com/careers to see how we empower creators to own their own destiny. Senior Software Engineer, Agent Runtime & Customer Workflows Customer Agent About the Role At Klaviyo, we believe the future of software lies not only in tools that help people work more efficiently, but in intelligent systems that can take action, learn from outcomes, and improve customer experiences over time. Klaviyo serves more than 167,000 customers and processes billions of consumer profiles, messages, interactions, and conversion signals. This creates a unique opportunity to build state-of-the-art AI systems that help businesses create and execute better customer experiences at scale. We’re looking for a Senior Software Engineer, Agent Runtime & Customer Workflows to join the Customer Agent team, Klaviyo’s AI-native conversational platform. You’ll design and build scalable backend systems and AI-powered product experiences that enable agents to reason, retrieve context, use tools, and take reliable action on behalf of customers. You’ll be expected to independently own meaningful technical problems, make pragmatic engineering tradeoffs, and help evolve the architecture and quality of the systems you work on. How You Will Make a Difference Design and build reliable, scalable backend systems and APIs that power AI-driven customer experiences. Build and evolve production agentic systems involving tool use, orchestration, context management, retrieval, structured outputs, and multi-step workflows. Solve hard applied AI problems across retrieval and RAG, grounding, model selection, hallucination mitigation, and deciding when deterministic or hybrid approaches are better than LLMs. Develop evaluation strategies using representative datasets, automated and human evaluation, regression testing, qualitative error analysis, and production signals. Improve production reliability through guardrails, fallbacks, retries, observability, monitoring, and thoughtful failure handling. Build asynchronous and distributed processing workflows that support high-volume AI workloads. Participate in an on-call rotation and help diagnose, mitigate, and learn from production incidents. Work directly with external customers and cross-functional partners to understand workflows, identify pain points, and translate feedback into product and technical improvements. Monitor shipped experiences and use customer behavior, quality metrics, and system performance to guide iteration. Who You Are You have 5-7 years of professional software engineering experience , with a strong foundation in backend systems and distributed applications. You have hands-on experience building and deploying generative AI or agentic AI applications into production for real users. You are proficient in Python and modern backend frameworks such as FastAPI or Django. You have experience with asynchronous processing and distributed task or event systems such as Celery, Kafka, SQS, RabbitMQ, or Redis. You have strong knowledge of databases, data modeling, APIs, and persistence patterns used in production systems. You are comfortable working in cloud-native environments with technologies such as AWS, containers, Kubernetes, infrastructure automation, or CI/CD systems. You can reason clearly about tradeoffs among quality, latency, cost, reliability, and implementation complexity. You are able to operate independently in ambiguous environments, break down loosely defined problems, and make pragmatic decisions about what to build first. You have experience with and genuine interest in working directly with external customers to understand problems and improve products. You care about shipping useful, reliable products and bring curiosity and sound engineering judgment to a rapidly evolving technical space. Nice to Have Experience training, fine-tuning, distilling, or otherwise adapting machine learning or language models for production use. Experience with reinforcement learning or feedback-driven optimization. Experience building evaluation infrastructure such as LLM-as-judge systems, evaluator calibration frameworks, benchmark suites, or AI quality platforms. Experience operating AI systems at substantial scale, including optimizing inference cost, latency, or throughput. #indeedRD 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 refl
| Role | Senior Software Engineer, Agent Runtime & Customer Workflows |
|---|---|
| Company | Klaviyo |
| Location | Boston, MA |
| Type | full-time |
| Compensation | Not disclosed |
| Posted | 2026-10-22 |
| Deadline | Rolling |
Typical process for this type of role
A general guide — the exact steps for this specific listing may vary; check the original posting for details.
- 1ApplicationSubmit your resume through the apply link.
- 2ScreeningRecruiter reviews your background against the role.
- 3AssessmentA technical test, assignment, or coding round, depending on the role.
- 4Interview(s)One or more rounds with the hiring team.
- 5OfferOffer letter with compensation and start date.
Before you apply
0/4About Klaviyo
Klaviyo, Inc. is an AI-first B2C CRM platform founded in 2012 and headquartered in Boston. The company provides a unified solution that integrates marketing automation, customer service, analytics, and a data platform to help businesses manage customer relationships. By centralizing behavioral, transactional, and engagement data, Klaviyo enables brands to deliver personalized, omnichannel campaigns across email, SMS, WhatsApp, and mobile push notifications. The platform utilizes AI agents to automate marketing tasks, resolve customer service inquiries, and optimize campaign performance. Klaviyo currently serves over 205,000 brands across more than 100 countries, processing billions of events and managing billions of customer profiles daily to support business growth.
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