Senior Software Engineer - Marketing Agent

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.

Job Title: Senior Software Engineer - Marketing Agent

Location: Boston, MA (Hybrid 3x week)

At Klaviyo, we believe the future of software lies not in productivity tools for human users but in systems that do the hard work for them. We’ve built the infrastructure and applications that power the interface between businesses and consumers — supporting over 183,000+ customers, billions of consumer profiles, and hundreds of billions of customer interactions. Now, we’re building the next generation of AI agents that can automatically create, execute, and optimize marketing and customer experience strategies for any business.

As a Senior Software Engineer on Klaviyo's Marketing Agent team, you'll be at the forefront of one of the most impactful bets we're making — building an AI-powered system that autonomously creates and executes high-stakes marketing strategies on behalf of thousands of customers. This isn't backend plumbing: the work you ship directly drives revenue for the businesses that rely on Klaviyo every day. Partnering closely with product managers and technical product owners, you'll shape the scope of what's possible, turn ambitious ideas into production reality, and craft tools so intuitive they feel like superpowers to the marketers using them.

This role is primarily backend, with a strong focus on crafting robust and maintainable AI powered systems that deliver high quality strategies and marketing content that’s ready to use to our customers. There are ample opportunities for growth given the scope of this role and the team’s central role in Klaviyo’s product.

How you’ll make a difference:

• You will dramatically increase ROI for Klaviyo customers by automating most of the marketing process for them.
• You will lead and design the next generation of agentic systems at Klaviyo, pushing the frontier of AI capabilities.
• You will collaborate with AI Engineers and AI Infra Engineers to ensure our system consistently produces high quality outputs at low latency.
• You will leverage your experience to mentor and level up junior team members on engineering best practices and patterns.
• You will transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up.

Who you are: 

• A proven track record of building high-quality products and systems, with pride in writing clean, high-quality code.
• 6+ years of experience in a software engineering role.
• Experience leading projects and being accountable for their outcomes.
• Experience mentoring team members or driving initiatives that help the team learn new skills.
• Experience conducting code reviews and running a robust testing cycle.
• Experience working in agile, fast-paced environments.
• Proficient in Python and modern web stack components such as FastAPI, Django, MySQL, Postgres.
• Experience working in cloud environments (AWS preferred).
• You’ve already experimented with AI in work or personal projects, and you’re excited to dive in and learn fast. You’re hungry to responsibly explore new AI tools and workflows, finding ways to make your work smarter and more efficient.

 Nice to have: 

• Prior work experience with AI tools such as Arize, Langgraph, Langchain
• Prior work experience building with LLMs such as GPT, Gemini, Claude

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

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).