Senior Software Engineer, Backend

Hi, I’m Paul, VP of Engineering at Customer.io. We’re looking for experienced backend engineers who care deeply about reliability, performance, and scalability. You’ll design, build, and evolve the systems that power communication at massive scale - while helping us push the boundaries of what great engineering can look like.

About Customer.io Over 9,000 companies - from scrappy startups to global brands - use our platform to send billions of emails, push notifications, in-app messages, and SMS every day. Customer.io powers automated communication that people actually want to receive. We help teams send smarter, more relevant messages using real-time behavioral data.

Under the hood: Go, React, Ember and AI help us ship fast and scale with confidence. What We Value Ownership You own problems end to end. You move fast, act like an owner, and thrive in ambiguity.

You've led complex projects before, whether officially or not, and you're ready to do it again. Engineers with product taste You think like a user, not just an engineer. You care how your systems power real customer value - and how to make them better.

A healthy skepticism for “the way things are done.” You bring rigor and creativity. Best practices matter - but never more than forward motion

What you’ll do

Design and build distributed systems in Go that help customers send timely, relevant messages at scale Collaborate across teams to debug issues and deliver reliable solutions Own problems end to end - from architecture and schema design to testing, deployment, and monitoring Participate in an on-call rotation as required, supporting the reliability of the systems you build Share knowledge and raise the bar through sharing your progress publicly with 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 What we're looking for 7+ years of experience building scalable, distributed systems in Go (or similar statically typed languages) Comfort working in cloud-native environments (AWS, GCP) Familiarity with relational databases (we use MySQL) and an understanding of performance tradeoffs Experience with observability tooling and operating production systems A bias for action over perfection, and pride in owning technical decisions Compensation & Benefits We believe in transparency.