Lead Software Engineer - Human User Access Team

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 youre a close but not exact match with the description, we hope youll still consider applying. Want to learn more about life at Klaviyo?

Visit to see how we empower creators to own their own destiny.

About the Team

The Human User Access (HUA) team is responsible for the core systems that ensure secure and seamless user authentication and authorization across our platform.

We design and maintain access control mechanisms, including role-based and custom roles, to provide flexible yet robust user management.

In addition to authentication services, we build and support internal tooling that empowers other teams, enhancing overall productivity and security.

Our focus is on scalability, security, and user experience, ensuring our systems can meet the demands of a growing, global user base.

How Youll Make a Difference

• Shape the Future of CIAM : Contribute to key projects in authentication, authorization, and access control, while driving the shift from a monolithic system to a scalable, service-oriented architecture.
• Own the Technical Vision : Lead the team in defining and executing the technical roadmap, aligning with strategic business goals and enabling long-term growth and innovation.
• Collaborate and Influence : Work closely with cross-functional teams to ensure our technical solutions support evolving product needs, directly impacting the user experience at scale.
• Drive Innovation : Implement architectural improvements that boost performance, scalability, and security, while ensuring adherence to industry best practices in code quality and infrastructure.
• Lead with Impact : Be a key player in delivering mission-critical services, including on-call support, ensuring system reliability and prompt resolution of issues in a high-traffic environment.

Champion industry best practices in code quality, infrastructure, and processes, ensuring the delivery of secure, efficient, and reliable solutions.

Tech Stack

• Python, Go, Django, GRPC
• MySQL, PostgreSQL, Redis, Memcache
• Apache Kafka, Apache Pulsar, RabbitMQ, Spark, Airflow, and other tech from the big data stack
• Typescript, React, Babel, Jest, Webpack
• AWS, Terraform, Docker, Kubernetes, Pantsbuild, BuildKite

Who You Are

• Proven expertise in building access control systems.
• Passionate about solving complex problems, with a strong ability to diagnose performance, scalability, and reliability issues, and implement breakthrough solutions.
• Extensive experience designing and driving system architecture decisions, balancing trade-offs between performance, scalability, security, and maintainability.
• A strong advocate for industry best practices, especially around security and protecting sensitive data in systems handling user privacy and data integrity.
• Strong leadership and mentorship skills, with a commitment to guiding and developing engineers at various levels.
• Excellent communication skills, with the ability to effectively convey technical concepts to both technical and non-technical stakeholders.
• Expertise in DevOps practices and tooling (CI / CD, containerization, orchestration), ensuring smooth integration, delivery, and maintenance of services in production environments.
• Experience in balancing immediate priorities with long-term goals, ensuring that tactical tasks align with strategic objectives while managing technical debt effectively.
• Bachelors degree or equivalent practical experience, with 10 years of experience in developing and launching complex software products, and 5 years of hands-on experience in software design and system architecture, focused on reliability and high performance.

Nice to Have

• Experience with microservices architecture and the transition from monolithic systems.
• Familiarity with identity management protocols such as OAuth, OpenID Connect, and SAML.
• Experience working in cloud environments (AWS, GCP, Azure) and leveraging cloud-native services.
• Hands-on experience with infrastructure-as-code (Terraform, CloudFormation) and container orchestration (Kubernetes, Docker).
• Knowledge of modern programming languages like Go or Rust
• Experience working with data privacy regulations (GDPR, CCPA) and ensuring compliance in software systems.
• Background in building developer tools or internal tooling to enhance productivity and efficiency for engineering teams.
• Familiarity with observability tools and practices (logging, monitoring, tracing) to ensure system health and reliability.
• Contributions to open-source projects or active participation in the tech community through talks, blogs, or conferences.

The pay range for this role is listed below. Sales roles are also eligible for variable compensation and hourly non-exempt roles are eligible for overtime in accordance with applicable law.

This role is eligible for benefits, including : medical, dental and vision coverage, health savings accounts, flexible spending accounts, 401(k), flexible paid time off and company-paid holidays and a culture of learning that includes a learning allowance and access to a professional coaching service for all employees.

Base Pay Range For US Locations :

$192,000 $288,000 USD

Get to Know Klaviyo

Were 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 were developing to nurture personalized experiences in ecommerce and beyond.

To reach our goals, we need our own crew of remarkable creatorsambitious and collaborative teammates who stay focused on our north star : delighting our customers.

If youre ready to do the best work of your career, where youll be welcomed as your whole self from day one and supported with generous benefits, we hope youll join us.

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.

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