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. Sr. Machine Learning Engineer Palo Alto, CA (Onsite 5x a week)   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 200,000+ 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 Sr. Machine Learning Engineer at Klaviyo, you will help build models that extract insights from the massive streams of data that Klaviyo ingests continuously. You will apply cutting-edge techniques from deep learning, recommender systems, language modeling, and more to integrate artificial intelligence into our product and bring customers value. You will need to deep dive into the product and the code to understand and contribute to solutions with your technical knowledge and experiences. You will be working with partners in Engineering, Product, and Design to solve challenging problems, and talking to stakeholders and customers firsthand.   Things you’ll do & make a difference • Train and deploy large-scale Machine Learning models in production systems to improve the values our product provide to our customers • Create AI engines or agents that can automatically create and execute marketing or customer experiences, strategies, and campaigns for any business and demonstrably outperform our human customers at Klaviyo. • Introduce conversational AI interfaces into our software to make our customers more efficient users of our products. • Build generative AI models that can automatically generate content for marketing given customer input on context, to maximize customer ROI or improve customers’ productivity. • Work in high impact environments with fast experimentation and product development cycles What we are looking for: • Advanced degree in Computer Science, Artificial Intelligence, Machine Learning, or a related field. • 5+ years of experience in AI, machine learning, or related fields, with a track record of successfully leading large-scale AI / machine learning projects launched in products with a significant impact on users / customers. • Experience with machine learning frameworks such as Huggingface, PyTorch, Tensorflow, Keras; Experience with distributed training with Spark, Ray, etc. • Experience leading technical projects and working with engineering teams and product managers successfully to deliver customer-facing features • Experience of developing and putting machine learning models into production, while also owning and maintaining production models long term • Experience owning the full product lifecycle of ML development, including defining success metrics, designing and analyzing A/B tests, and iterating based on result • Experience mentoring others   Nice to have: • Experience with recommendation systems, including designing, training, and deploying recommendation models, as well as building retrieval and ranking systems. • Experience working in B2B businesses and interacting with customers directly • Experience developing technical roadmaps for solving complex business problems using Machine Learning • Experience fine-tuning and productionizing transformer-based models at scale, particularly large language models. 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: $196,000—$294,000 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 (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.  By participating in Klaviyo’s interview process, you acknowledge that you have read, understood, and will adhere to our Guidelines for using AI in the Klaviyo interview Process. For more information about how we process your personal data, see our Job Applicant Privacy Notice. 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).