Senior Lead Software Engineer; Mobile Channels

Requirements

• Experience:
  
  12+ years of software engineering experience with a strong track record building and scaling distributed backend systems. Prior time as a Lead, Staff, or Principal engineer driving technical direction across multiple teams
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• Hands-On Technical Depth:
  Proficient in Python and/or Go, and able to rapidly learn the other. Comfortable coding, reviewing, and debugging complex systems — this is a hands-on role
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• Distributed Systems Expertise:
  Deep experience with high-throughput, event-driven, distributed architectures — ingestion pipelines, async processing, stateful workloads, eventing patterns, multi-region/data-locality concerns, and the failure modes that come with all of it
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• Architectural & Strategic
  
  Skills:
  
  Demonstrated ability to define technical strategy and drive cross-team architectural decisions in ambiguous, high-stakes environments — and to commit to a call even when there's disagreement, backed by data and prototypes
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• Cloud & Platform:
  Strong experience with AWS at scale; comfortable with Infrastructure as Code (Terraform), containerization, and modern observability stacks (metrics, logs, traces, SLI/SLO design)
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• Business & Product Mindset:
  You think beyond the code — you understand customer impact, commercial value, and the cost-vs-conversion tradeoffs that come with mobile messaging — and you bring that mindset into architectural decisions
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• Influence & Communication:
  Exceptional communicator; can articulate complex technical concepts to engineers, product leaders, and executives, and can rally multiple teams toward sequenced, realistic improvements
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• AI Enthusiast:
  You've already experimented with AI in work or personal projects, and you're excited to dive in and learn fast. You're hungry to responsibly explore new AI tools and workflows, finding ways to make your work — and the systems you build — smarter and more efficient
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• Collaborative & Self-Led:
  Strong cross-functional partner; thrives in a hybrid team and high-autonomy environment; ships value early and iterates
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• (Desirable) Experience with the SMS, RCS, or Whats App ecosystems, including channel-specific protocols, opt-in/opt-out semantics, and familiarity with key 3rd-party entities (carriers, providers, regulators) and compliance rules and best practices
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• (Desirable) Background in performance optimization and a passion for digging into performance, scalability, and reliability issues to drive breakthrough solutions across distributed systems
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• (Desirable) Experience with multi-region deployments, data residency, and large-scale data or service migrations with minimal downtime
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• (Desirable) Familiarity with complex data management for testing, including large datasets and production-like data replication

• The Mobile Channels team at Klaviyo powers text messaging across Klaviyo's platform — SMS, RCS, Whats App, and a growing set of future text messaging channels
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• Mobile is one of Klaviyo's fastest-growing product areas: as brands shift more of their owned-channel investment to mobile, our team builds the infrastructure that makes high-throughput, reliable delivery possible across a complex, multi-channel landscape
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• We own the systems that connect Klaviyo customers to their audiences through the fastest and most personal communication channels available — at scale, across geographies, and against a constantly evolving set of carrier, regulatory, and provider constraints
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• As a Senior Lead Software Engineer on the Mobile Channels team, you'll be the technical area lead for Mobile Channels — driving architecture and technical direction across the SMS, RCS, and Whats App teams, and the new channels we'll add next
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• You'll define the cross-team technical roadmap for the pillar, own the architectural patterns that bind the channels together (ingestion, routing, provider integration, status tracking, compliance automation, deliverability), and lead the most complex, multi-team initiatives end-to-end
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• This is a hands-on technical leadership role: you'll contribute to architecture and code, lead design reviews, mentor Lead and Senior engineers across multiple teams, and partner closely with Engineering Managers to…