Lead AI Engineer

Klaviyo; City Of London; On-site; GBP 140,000; Full time

Job summary

A leading technology company in London seeks a Lead Software AI Engineer to oversee backend systems and AI-driven user experiences. The role involves designing scalable solutions, mentoring engineers, and leading AI product strategy. Applicants should have significant experience with AI/ML technologies, backend frameworks, and distributed architectures. Competitive salary of £140,000 offered along with comprehensive benefits.

Benefits

Annual cash bonus plan

Comprehensive health benefits

Qualifications

• 7–10 years of professional software engineering experience focusing on backend systems.
• Hands-on experience with AI/ML and large language models (LLMs).
• Proven ability to design and scale distributed systems.

Responsibilities

• Lead the design and development of AI solutions for over 167K customers.
• Architect distributed data pipelines for AI/ML models.
• Mentor engineers and drive technical excellence.

Skills

Backend systems design

Applied AI/ML

Python

Distributed architectures

Big data tools

API architecture

Technical leadership

Tools

FastAPI

Django

Apache Spark

Kafka

AWS

Job description

Overview

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 careers.klaviyo.com to see how we empower creators to own their own destiny.

Role

Lead Software AI Engineer

As a Lead Software AI Engineer at Klaviyo, you’ll set technical direction and drive the design of scalable backend systems and AI-powered user experiences that form the foundation of our AI product strategy. You’ll work closely with product managers, machine learning engineers, and data scientists while mentoring engineers and shaping architectural decisions. This is a backend-heavy leadership role with a strong focus on applied AI/ML, including large language models (LLMs) and agentic AI systems.

Responsibilities

• Lead the design and development of backend systems that enable scalable AI solutions for 167K+ customers.
• Architect robust, reliable, and scalable data pipelines that train and serve AI/ML models at scale.
• Drive the integration of LLMs into production systems, powering AI agents that create and execute real-time customer experiences.
• Establish best practices for model evaluation, monitoring, and performance across generative and agentic AI use cases.
• Mentor and guide engineers, fostering a culture of technical excellence, ownership, and customer-centric product thinking.
• Partner with cross-functional leaders to influence AI product strategy and deliver high-impact solutions.

Qualifications

• 7–10 years of professional software engineering experience, with a strong focus on backend systems and distributed architectures.
• Recent, hands-on experience with AI/ML and LLMs, including fine-tuning, evaluation, and production deployment.
• Proven ability to design and scale distributed systems that support AI-driven applications and agent capabilities.
• Proficient in Python and modern backend frameworks (FastAPI, Django preferred).
• Skilled with big data tools (Apache Spark, Hadoop) and distributed task queues (Kafka, Celery, SQS, RabbitMQ, Redis).
• Experienced in architecting APIs and cloud-native solutions (AWS, Kubernetes, CI/CD pipelines).
• Demonstrated technical leadership — mentoring engineers, shaping architecture, and raising the bar for engineering practices.
• Thrives in a fast-paced, startup-like environment with high autonomy and ownership.
• Curious, adaptable, and motivated to stay on the cutting edge of AI/ML research and apply it to real-world business challenges.

Nice to Have

• Experience training and deploying reinforcement learning systems.
• Prior experience leading cross-functional initiatives involving data science, ML engineering, and product.

Additional Information

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.

Our salary range reflects the cost of labour in the country where the job post is advertised. 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. Please visit Klaviyo Rewards - Global Benefits to find out more about our Total Rewards package.

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

Base Pay Range in Local Currency: £140,000 — £140,000 GBP

Get to Know Klaviyo

We’re Klaviyo (pronounced clay-vee-oh). 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 ecommerce and beyond. To reach our goals, we need our own crew of remarkable creators—ambitious and collaborative teammates who stay focused on our north star: delighting our customers. If you’re ready to do the best work of your career, where you’ll be welcomed as your whole self from day one and supported with generous benefits, we hope you’ll join us.

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

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, religion or religious creed, age, sex (including pregnancy), gender identity, sexual orientation, physical or mental disability, veteran or active military status, marital status, criminal record, genetics, retaliation, sexual harassment or any other characteristic protected by applicable law.

IMPORTANT NOTICE: Our company takes the security and privacy of job applicants very seriously. We will never ask for payment, bank details, or personal financial information as part of the application process. All our legitimate job postings can be found on our official career site. Please be cautious of job offers that come from non-company email addresses (@klaviyo.com), instant messaging platforms, or unsolicited calls. By clicking "Submit Application" you consent to Klaviyo processing your Personal Data in accordance with our Job Applicant Privacy Notice. If you do not wish for Klaviyo to process your Personal Data, please do not submit an application. You can find our Job Applicant Privacy Notice here and here (FR).