Software Engineer I

Klaviyo Campus; Boston (MA); On-site; USD 104,000 - 156,000; Full time

Job summary

Klaviyo in Boston is seeking a Software Engineer I to join our early‑career ranks. You'll write, test, and deploy code for features used by thousands of paying customers, working on scalable systems and AI‑enhanced workflows in a fast‑paced, product‑driven environment.

This role offers hands‑on learning, collaboration with experienced engineers, and opportunities to grow across the stack from back‑end to front‑end. Graduates or new grads joining in Dec 2026 to May/June 2027 encouraged to apply.

Qualifications

• Two internship/co-op roles with production‑level code.
• Pursuing a degree in Computer Science, Engineering, Data Science, Math/Statistics, or related field.
• Graduating in December 2026 or May/June 2027.
• Experience with Python, Django, Typescript, React, Go.
• Experience with MySQL, Cassandra, Clickhouse, Kafka, Redis.
• Experience with AWS (EC2, RDS, Aurora), Terraform.

Responsibilities

• Own features that our 180K+ paying customers rely on daily to reach their consumers and grow their business.
• Take responsibility for the mission, technical direction, and operation of projects with immediate impact.
• Own the full lifecycle of your code: writing it, testing it, shipping it, and making it better over time.
• Build and ship features that meet a high bar and grow your technical skills while you do it.
• Get hands‑on debugging real issues, both locally and in production.
• Contribute to documentation and support your team during incidents.
• Work closely with your teammates: ask questions, share ideas, and get better by taking feedback seriously.

Skills

Python

Django

Typescript

React

Go

Education

Pursuing CS/Engineering/Data Science degree

Tools

MySQL

Cassandra

Clickhouse

Kafka

Redis

AWS

Terraform

Job description

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.

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What's it like to ship code that thousands of people actually use? As a Software Engineer at Klaviyo, you'll find out fast. We're builders here: we run toward problems, hold ourselves to a high bar, and believe the work itself is the reward. Another payoff of this early career role is growth. You'll sharpen your skills, learn from engineers who've been in the trenches, and get your hands on projects that matter from day one.

Our engineering teams build scalable, high-performance systems that power both our product and the infrastructure behind it. In this role, you'll get exposed to modern infrastructure and engineering practices that allow you to grow as a software engineer. We're an AI-first company, so you'll be expected to use AI tools to move faster, learn quicker, and do better work.

You'll have ownership: writing and testing code, documenting it, deploying it, and keeping it running in production. If you're ready to launch your engineering career building systems that matter in a fast-moving, product-driven environment, this is your role.

Dec 2026 grads: start dates on a rolling basis.
Spring 2027 grads: start dates June–August.

How you'll make an impact

• Own features that our 180K+ paying customers rely on daily to reach their consumers and grow their business.
• Take responsibility for the mission, technical direction, and operation of projects with immediate impact.
• Own the full lifecycle of your code: writing it, testing it, shipping it, and making it better over time. Ownership is expected here, not just encouraged.
• Build and ship features that meet a high bar and grow your technical skills while you do it.
• Get hands‑on debugging real issues, both locally and in production.
• Contribute to documentation and support your team during incidents (real-world problems teach you things a tutorial never will).
• Work closely with your teammates: ask questions, share ideas, and get better by taking feedback seriously.
• Learn to use the right tool for the job, lean into AI, and keep looking for ways to make things better.
• Put AI at the center of how you work to move faster. Build smarter systems and better workflows from the ground up.

Who you are

• Two previous internship/co‑op roles working with production‑level code
• Currently pursuing a degree in Computer Science, Engineering, Data Science, Math/Statistics, or a related field
• Graduating in December 2026 or May/June 2027
• Experience with some of these technologies and languages:
  • Python, Django, Typescript, React, Go
  • MySQL, Cassandra, Clickhouse, Kafka, Redis
  • Amazon Web Services (EC2, RDS, Aurora, etc.), Terraform
• You enjoy working across new technologies and you’re excited to work across the stack from back‑end to front‑end work
• You give and take feedback directly. Klaviyos pull problems closer instead of avoiding them.
• You're comfortable moving forward before every answer is known, and you adjust fast when the ground shifts under you.
• You embrace Klaviyo's "always learning" culture, continually pushing yourself to grow as an engineer.
• You've already experimented with AI in work or personal projects, and you're excited to find ways to make your work smarter and more efficient.

Engineering at Klaviyo

Our engineering teams are organized into pillars to keep the work focused. All Software Engineer I offers are team agnostic. Team placement occurs ~ 30-day pre-start. Placement can be on a full-stack, back-end, or front-end team within any of the pillars.

• Data Infrastructure: Empower our internal teams and customers to get the best out of our data and agent platforms. underlying capabilities: Agent Platform, CDP revenue, Data Lake usage, Active API endpoints, Accounts with healthy API usage
• MCMI: Own the growth, revenue, and reliability of our mobile channels and all messaging infrastructure.
• Core Infrastructure: Empower our internal engineering, sales, and service teams to be as effective as possible by improving productivity of the eng, product, and design teams.
• Growth Marketing Platform: Give marketers the tools they need to engage with their customers, be successful, and know where they stand.
• AI & Analytics: Applies AI, data, and analytics to automate work, surface insights, and help customers make smarter decisions that maximize Klaviyo Attributed Value (KAV).
• Autonomous Service: Builds AI-powered customer service experiences that help resolve issues, support transactions, and connect customers with human assistance when needed.

If you're excited about this role but your background doesn't check every box, apply anyway. Some of the strongest Klaviyos didn't start with a perfect resume match.

This role is not eligible for immigration sponsorship.

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

$104,000 — $156,000 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.

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.

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