Senior Software Engineer

About the role

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 klaviyo.com/careers to see how we empower creators to own their own destiny. This role centers on owning the technical strategy and execution for our backend platform. You will analyze, design, and deliver foundational systems that keep our codebase healthy and scalable across the entire organization. You will drive dependency management, platform upgrades, and productivity initiatives that directly impact engineering velocity. This position requires hands-on leadership in both strategic planning and individual contribution to complex technical challenges. You will partner closely with security, product, and other engineering teams to define standards and roll out platform changes. Ultimately, you will ensure every engineer at Klaviyo can move fast with confidence through robust and reliable infrastructure.

Key facts

What you'll do

Analyze and optimize backend and third-party dependencies across the Klaviyo codebase to ensure a healthy, performant, and maintainable dependency graph.

Lead the planning and execution of major software releases and platform upgrades, including hands-on coding through production rollout and validation.

Drive improvements in key cycle time metrics such as PR CI speed, code review turnaround, and commit velocity by reducing toil and increasing engineering efficiency.

Define and advocate for engineering standards focused on code quality, dependency hygiene, and platform reliability that all teams adopt and follow.

Spearhead the evaluation and implementation of AI-driven strategies within the platform lifecycle and utilize AI tooling to accelerate personal development work.

Partner with engineers, security teams, and stakeholders to gather requirements, resolve conflicts, and enable confident adoption of platform changes.

Proactively monitor the health and reliability of platform infrastructure, diagnosing and resolving complex issues before they escalate into critical incidents.

Design and implement developer productivity tools that reduce manual effort and streamline workflows across the engineering organization.

Evaluate emerging technologies and frameworks, and lead technical assessments for their potential adoption within our backend systems.

Champion best practices for security and compliance as they relate to platform dependencies and infrastructure changes.

Collaborate with cross-functional teams to ensure platform initiatives align with business objectives and technical constraints.

Document and communicate platform decisions, trade-offs, and operational procedures to ensure clarity and continuity across engineering teams.

Requirements

Candidates must possess 5+ years of professional software engineering experience with a strong focus on clean, maintainable, and well-architected code.

Demonstrate deep understanding of computer science fundamentals and backend engineering principles including system design, data structures, and algorithms.

Show proven ability to analyze complex systems, identify root causes, and implement systemic fixes that prevent recurring issues.

Bring experience managing and optimizing dependency graphs within large, multi-repository codebases.

Have a history of contributing to or leading platform upgrades and major software releases in a production environment.

Exhibit strong written and verbal communication skills for collaborating with cross-functional stakeholders and documenting technical decisions.

Comfortable working in a fast-paced, dynamic environment where priorities can shift based on business needs and technical challenges.

Committed to building inclusive and collaborative team environments where diverse perspectives are valued and respected.

Nice to have

Experience with AI tooling and workflows to enhance development processes and platform capabilities.

Familiarity with modern frontend build systems and developer experience improvements.

Background in security-focused dependency analysis and risk evaluation frameworks.

Practical notes

Employment is full-time.

This role is based in Boston, MA.

Candidates must be authorized to work in the United States without sponsorship for this position.