Full Stack Software Engineer - People Systems

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. Klaviyo is building an AI-first company—and that starts with how we support and scale our people. We’re looking for a Lead People Technology Engineer to be the first dedicated AI engineer within our People Technology (KPPL) team. As an early leader in this space, you’ll reimagine how our People teams operate in an AI-first world by shaping our architecture, standards, and long-term vision. You’ll partner across People Operations, Talent Acquisition, Talent, and Finance to design and build intelligent systems that transform how we hire, develop, retain, and support Klaviyos globally. This role is not just about applying AI it’s about defining how AI becomes embedded into the employee lifecycle at Klaviyo. What You’ll Be Doing AI-First People Systems & Architecture • Reimagine core People workflows (recruiting, onboarding, performance, daily tasks) through an AI-first lens, not just incremental automation • Design and build AI-powered workflows, copilots, and agents that automate and augment People processes across the employee lifecycle • Architect and implement systems that integrate across SaaS such as Workday, Greenhouse, Sana, and internal Klaviyo platforms • Partner with our internal IT AI team and establish best practices for: • Prompt engineering and evaluation • LLM system design and orchestration • Versioning, testing, security, and observability of AI systems • Enable AI Use Cases (copilots, assistants, automated workflows) that drive faster execution and better decision-making for People teams • Collaborate with stakeholders to translate business problems into scalable AI solutions Driving an AI-First Operating Model • Identify high-leverage opportunities to replace manual workflows with AI-native solutions • Define and track success metrics tied to efficiency gains, time savings, and operational effectiveness • Help the People organization shift toward AI-augmented ways of working • Act as a thought partner to People leadership on what’s possible with AI, not just what’s requested • Responsible AI, Privacy & Governance: Design systems that handle sensitive employee data with security, privacy, and trust at the core • Partner with Security, Legal, and Global IT to ensure compliant and ethical AI deployment Cross-Functional Collaboration & Enablement • Work closely with Security, IT, and GTM Systems to align on shared AI infrastructure and standards • Contribute to and adopt company-wide AI patterns, tooling, and best practices • Enable People teams to leverage AI by building: • Reusable frameworks and workflows • Playbooks and training materials • Help non-technical stakeholders confidently use and iterate on AI-powered tools Technical Leadership • Advocate for scalable, well-governed AI systems that integrate cleanly into Klaviyo’s broader tech ecosystem • Act as a key voice in shaping how Klaviyo becomes AI-first internally, starting with People systems What Makes You a Great Fit • Passion and Curiosity to experiment and reimagine People workflows • 5+ years of engineering or data engineering experience, with 2+ years building AI/ML or LLM-powered delivering tangible business outcomes • Proven ability to set technical direction and build 0→1 systems with meaningful organizational impact • Strong experience with but not limited to: • Python, SQL, and modern APIs • LLM platforms (OpenAI, Claude, Gemini, etc.) • LangChain and LangGraph • Designing AI-powered workflows, agents, or copilots • Experience integrating with enterprise SaaS systems (HRIS, ATS, etc.) • Experience designing scalable systems, automation frameworks, and internal tools • Experience working with sensitive data and implementing responsible AI practices • Strong ability to translate ambiguous business problems into scalable technical solutions Bonus Points • Experience with People/HR systems (Workday, Greenhouse, Sana) • Familiarity with workflow automation platforms (e.g., n8n, Workato, Zapier) • Experience in high-growth SaaS environments • Contributions to AI governance, internal AI platforms, or experimentation frameworks Why This Role Matters at Klaviyo This is a foundational role in defining how Klaviyo becomes an AI-first company from the inside out. You won’t just be implementing AI you’ll be: • Shaping how People teams operate with AI • Defining standards for responsible, scalable internal AI systems • Building the blueprint for how AI is embedded across the business If you’re excited about building from scratch, influencing across functions, and applying AI to core business workflows, this role offers a unique opportunity to have outsized impact. 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)