Senior Security 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 to see how we empower creators to own their own destiny.

As a Senior Security Engineer, you'll be a vital part of the Infrastructure Security Team, focusing on strengthening the security posture across Klaviyo's entire technology environment. Unlike roles with a narrowly defined specialty, this position offers the opportunity to demonstrate your unique expertise—whether that's in cloud security, identity and access management, data protection, secure systems design, or other security domains. Your work will involve evaluating and hardening our infrastructure, collaborating with cross-functional teams, and leveraging AI to  build scalable solutions to address emerging threats.

We are looking for someone who is excited to bring their specialized skills to the team, shaping Klaviyo's security practices and helping us continue to raise the bar.

How You Will Make a Difference

• Secure Klaviyo's infrastructure by designing, implementing, and maintaining scalable security controls across cloud, on-prem, and hybrid environments
• Evaluate and improve security configurations and policies across a range of technologies, using your domain expertise to reduce risk and enable secure-by-default architectures
• Collaborate with engineering and IT teams to embed security practices across the development and deployment lifecycle
• Lead threat modeling, risk assessments, and architecture reviews in areas aligned with your specialty
• Develop automated solutions and infrastructure-as-code to drive consistent and reproducible security outcomes
• Stay ahead of the latest threats and advocate for innovative security solutions aligned with business needs
• Help define security standards and best practices at Klaviyo, championing their adoption across teams

Who You Are

• Have 3+ years of experience in infrastructure or security engineering roles, with deep knowledge in one or more security focus areas (e.g., cloud security, IAM, endpoint security, data protection, detection engineering, compliance)
• Comfortable navigating ambiguity and defining priorities in a broad-scoped role
• Experienced working in modern cloud environments such as AWS, GCP, or Azure
• Familiar with infrastructure-as-code tools such as Terraform, CloudFormation, or Pulumi
• Proficient in secure systems design, threat modeling, and vulnerability management
• AI Agentic development and prompt engineering, MCP (AWS Bedrock, OpenAI, Anthropic)
• Able to clearly articulate complex security topics to technical and non-technical stakeholders
• Passionate about security, eager to learn from others and share your expertise
• Nice to have -  certifications (e.g., CISSP, CKS, GCP/AWS Security certs) or equivalent practical experience

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: $152,000—$228,000 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 ), 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).

---