Senior Software Engineer - Amplify at Klaviyo

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.

Team Overview:

The Amplify Engineering team builds internal tools, platforms, and AI-powered automation that help Klaviyos work more efficiently and at scale as the company grows. We partner across the organization, including Sales, Marketing, Engineering & Product, Customer Service & Success, and Finance, to solve real operational problems with practical, well-designed software.

Our work spans internal applications, 3rd-party integrations, interactive dashboards, CMS integrations, and robust AI systems and agents that automate repetitive tasks, surface the right information at the right time, and help teams make better decisions. We operate in tight feedback loops with our internal customers, shipping quickly, learning fast, and seeing the impact of our work immediately in how deals move faster, tickets resolve sooner, and launches go more smoothly.

This role is for senior engineers who enjoy turning real-world problems into reliable, scalable solutions. The work is highly visible and has a direct impact on how thousands of Klaviyos get their work done every day.

How You’ll Make an Impact:

The Amplify team builds the internal platforms, automation, and AI-driven systems that power how Klaviyos work every day. As a Senior Software Engineer on Amplify, you will:

Design, build, and own complex internal products and platforms, including internal web applications, APIs, data and event pipelines, and AI-powered workflows that directly impact how Sales, Marketing, Customer Service & Success, R&D, and Finance teams operate day to day.
Independently lead the end-to-end lifecycle of projects and features – from discovery and design through implementation, rollout, and long-term ownership.
Translate real operational problems into scalable, maintainable solutions. You’ll partner closely with internal customers to understand their workflows and constraints, then design pragmatic, AI-first software that measurably improves throughput, quality, and reliability of their work.
Own the technical and architectural evolution of parts of the Amplify platform, anticipating scalability, reliability, and observability needs as usage grows and as Klaviyo’s AI strategy evolves.
Establish, refine, and uphold SLOs and operational health for the systems you own, ensuring they are reliable, observable, and fit for internal customer needs, including incidents, on-call participation, and follow-through on RCA actions.
Drive an AI-first engineering workflow. You’ll use modern AI tools (e.g., OpenAI/Anthropic/Gemini models, Claude Code, Cursor, Copilot, etc.) for design, coding, testing, and documentation, and help define best practices for how Amplify engineers use AI to safely and efficiently ship software.
Create and evolve shared patterns, tools, and processes that make it easier for Amplify and adjacent teams to build internal tools and AI agents consistently and at high quality (e.g., templates, SDKs, integration patterns, evaluation harnesses, observability standards).
Mentor and uplevel other engineers on the team through design reviews, pairing, feedback on technical documents, and by modeling excellent engineering practices that leave the codebase, systems, and processes better than you found them.
Collaborate deeply with Product, Design, Data, and operational stakeholders to define requirements, trade-offs, and success metrics, ensuring Amplify’s systems are solving the highest-value problems with clear, measurable outcomes.
Transform workflows by putting AI at the center, building smarter systems and ways of working from the ground up.

Who You Are:

You are passionate about building software effectively and for the long term, balancing technical quality, velocity, and business impact.
BA or BS Degree in Computer Science, related field, or equivalent experience.
You typically bring 6+ years of hands-on software development experience building and operating highly available, full-stack SaaS products at scale, or have demonstrated equivalent proficiency and impact.
You are independently responsible for the full lifecycle of complex projects or features, including discovery, technical design, implementation, rollout, and ongoing maintenance. You provide clear technical direction for others involved.
You have deep expertise in one or more areas of modern web architecture (e.g., backend services, data pipelines, internal tools, AI/ML infrastructure) and a strong understanding of scalable, multi-tenant design patterns.
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.
You are an AI-native engineer. You regularly use AI tools (e.g., OpenAI/Anthropic/Gemini models, Claude Code, Cursor, Copilot, etc.) to accelerate development, improve code quality, and explore new solutions, and you’re excited to push the team’s AI-augmented workflows forward responsibly.
You own the operational health of the systems you build, including performance, reliability, and observability. You are comfortable defining and upholding SLOs, participating in on-call, and driving follow-through on incidents and RCAs.
You question convention and proactively look for ways to improve, whether that’s workflows, architecture, tooling, or team processes. You are intrinsically motivated to drive incremental and step-change improvements that deliver value to the business.
You are an excellent communicator and collaborator. You lead technical discussions at the project and product-area level, write clear technical design documents and RFCs, and keep stakeholders aligned on progress, risks, and trade-offs.
You mentor and support other engineers, offering thoughtful feedback in design and code reviews, helping refine specifications, and investing in the growth of more junior engineers on the team.
You enjoy working on small, autonomous, agile teams, shipping early and often, pairing with product managers, business stakeholders, and other engineers to craft better software.

Nice to Have:

Experience building internal tools, platforms, or automations for developers and/or non-technical stakeholders, with a track record of improving reliability, productivity, or operational efficiency.
Hands-on experience in full-stack environments, including diagnosing and improving application performance, database queries, and complex, multi-service workflows.
Practical experience building or integrating AI-powered systems and agents; e.g., workflows using LLM APIs/SDKs, agentic or automated workflows, RAG pipelines, or evaluation/monitoring frameworks.
Familiarity with cloud infrastructure (AWS preferred), infrastructure-as-code (Terraform), and containerized environments (Kubernetes), including how to design services that run reliably at scale in those environments.

Technologies We Use:

Klaviyo’s platform is primarily built with Python and React and runs on AWS. Engineers join us from a wide range of technical backgrounds and are supported in learning our stack. Core technologies include:

Python / Django / FastAPI
Typescript / React
MySQL / Redis / Memcached
RabbitMQ / Celery / Apache Kafka / Apache Pulsar
AWS / Terraform / Kubernetes

Location & Work Model:

This role is based in Boston, Massachusetts and follows a hybrid working model. Klaviyo supports work authorization and relocation for this position.

At Klaviyo, we enjoy tackling meaningful engineering challenges and value people who take ownership, learn continuously, and collaborate openly. We are committed to building inclusive teams and encourage applications from candidates of all backgrounds.

Klaviyo is growing fast and we have openings for all skill levels across all of our teams. Learn more about our engineering culture at https://klaviyo.tech

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).

Senior Software Engineer - Amplify

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