Senior Software Engineer - Email Channel

About the Role

Customer.io is looking for an experienced Senior Software Engineer to own our Email Channel end-to-end. You will work across the stack, from the infrastructure that delivers billions of messages reliably to the product surfaces our customers use to build, send, and analyze their campaigns.

Note: You do not need prior email domain experience to apply; we value engineers who love learning deep problem spaces.

What You'll Do

• Frontend: Build and evolve customer-facing experiences including editors, configuration, and analytics dashboards.
• Backend: Design and scale high-volume systems for message processing, queue management, retry logic, rate limiting, and real-time event pipelines.
• Automation: Build intelligent systems for feedback signals, suppression, throttling, and health scoring.
• Collaboration: Partner with domain experts to turn email knowledge into automated tooling.
• Observability: Instrument and monitor channel health, including anomaly alerting and signal detection.
• Ownership: Own problems from architecture and schema design to testing, deployment, and monitoring.
• AI Integration: Utilize AI agents to scope work, write prompts, and verify multi-file changes.

What We're Looking For

• 7+ years of experience building scalable, distributed systems in Go (or similar statically typed languages).
• Experience building product-facing frontend features in React or similar frameworks.
• Experience with high-throughput async workloads (event streams, queues).
• Comfort integrating with external third-party APIs and designing for resilience.
• Experience in cloud-native environments (AWS, GCP) and relational databases (MySQL).
• Strong understanding of observability tooling and production operations.
• A bias for action and pride in technical ownership.

Nice to have: Familiarity with email infrastructure (deliverability, SPF/DKIM/DMARC, sender reputation).

Benefits

• Salary: $150,000 - $200,000 USD.
• 100% coverage of medical, dental, vision, mental health, and supplemental insurance for you and your family.
• 16 weeks paid parental leave.
• Unlimited PTO.
• Remote work and wellness stipends.
• Professional development budget.