Principal Engineer

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.

The Role

As a Principal Software Engineer, you will operate at the highest technical level within the company, shaping the architecture, scalability, and long-term vision of our core platform and systems. You’ll lead cross-functional initiatives, set engineering standards, and mentor the next generation of technical leaders. This is a hands-on role with strategic impact, blending deep technical work with high-level architectural leadership.

Responsibilities

• Drive the architectural direction for large-scale systems that support high availability, scalability, and security.
  
  
• Lead high-impact projects across multiple teams and functions, ensuring alignment with company-wide technical strategy.
  
  
• Act as a technical advisor to senior leadership; contribute to long-term product and infrastructure planning.
  
  
• Mentor and develop senior engineers; serve as a multiplier across the organization.
  
  
• Conduct design and code reviews, ensuring best practices in performance, reliability, and maintainability.
  
  
• Evaluate and introduce new technologies, frameworks, and tools to improve development velocity and product quality.
  
  
• Partner with Product, Data, DevOps, and Security teams to ensure end-to-end excellence.
  
  
• Represent the engineering organization in cross-company forums and technical deep-dives.
  
  

Requirements

• 12+ years of professional software engineering experience, with a proven track record of technical leadership and architectural design.
  
  
• Deep expertise in one or more programming languages and scalable distributed systems.
  
  
• Experience leading engineering initiatives in cloud-native environments.
  
  
• Strong systems design skills and a background in designing resilient, performant architectures.
  
  
• Demonstrated success mentoring and scaling high-performing engineering teams.
  
  
• Excellent communication and collaboration skills; able to influence stakeholders at all levels.
  
  
• BS/MS in Computer Science or related field—or equivalent experience.
  
  

Nice to Have

• Experience in a high-growth, post-IPO or public company.
  
  
• Familiarity with modern DevOps practices (CI/CD, observability, SRE).
  
  
• Experience in regulated or security-sensitive industries (e.g., fintech, healthtech, enterprise SaaS).
  
  
• Contributions to open-source projects or technical publications.

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. Please visit Klaviyo Rewards to find out more about our Total Rewards package.

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