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 8,000 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
• 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

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