Senior Software Engineer – Email Channel

Customer.io

Senior Software Engineer building email channel infrastructure at Customer.io. Involves both frontend and backend systems for high-volume email sending and analytics.

Posted 5/12/2026full-timeRemote • 🇺🇸 United StatesSenior💰 $150,000 - $200,000 per yearWebsite

Tech Stack

Tools & technologies

AWSCloudDistributed SystemsGoGoogle Cloud PlatformMySQLReact

About the role

Key responsibilities & impact

Build and evolve the frontend experiences customers use to create, preview, and analyze email campaigns — template editors, sending configuration, deliverability dashboards
Design and scale the backend systems that power high-volume email sending, including queue management, retry logic, and event processing (bounces, complaints, deferrals)
Own deliverability-adjacent systems: bounce classification, suppression management, IP/domain reputation monitoring, and feedback loop processing
Partner with our deliverability team to translate domain expertise into automated tooling — reputation scoring, warm-up schedules, sending throttles
Instrument and monitor the health of the email channel: inbox placement signals, block detection, ESP feedback, and alerting
Own problems end to end — from architecture and schema design to testing, deployment, and monitoring
Share knowledge and raise the bar through short videos, thoughtful writing, and mentorship
Use AI agents to make multi-file changes by scoping the work, writing the prompt, and verifying the output

Requirements

What you’ll need

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, with attention to UX quality and polish
Comfort working in cloud-native environments (AWS, GCP)
Familiarity with relational databases (we use MySQL primarily) and an understanding of performance tradeoffs
Familiarity with high-volume email sending concepts: bounce handling, feedback loops, and delivery event processing
Working knowledge of email authentication standards — SPF, DKIM, DMARC — and how they affect deliverability
Comfortable reasoning about sender reputation, IP warm-up, and ISP behavior at scale
Experience with observability tooling and operating production systems
Experience building or consuming APIs that handle high-throughput async workloads
A bias for action over perfection, and pride in owning technical decisions.

Benefits

Comp & perks

100% coverage of medical, dental, vision, mental health, and supplemental insurance premiums for you and your family
16 weeks paid parental leave
unlimited PTO
stipends for remote work and wellness
a professional development budget

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills & Tools

GoReactAWSGCPMySQLemail authentication standardsSPFDKIMDMARCAPI development

Soft Skills

mentorshipcommunicationproblem-solvingattention to UX qualitybias for actionownership of technical decisions