Staff Software Engineer, Backend

Hi, I'm Paul, VP of Engineering at Customer.io. We're looking for a staff engineer to set technical direction for the systems that move billions of messages a day. This isn't a role about shipping more, faster. It's about deciding what gets built, where the architecture needs to go next, and raising the ceiling for ...

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.

Shape the technical direction of our distributed messaging systems in Go — making the high-level architectural calls on mission-critical services where scale, cost, and reliability are all in tension
Take on ambiguous, high-stakes problems that cross squad and function boundaries, and drive them to a decision when the right answer isn't obvious to anyone yet
Build consensus on contested technical questions across teams, and communicate the tradeoffs clearly enough that senior leadership can act on them
Raise the department's bar — set quality and design standards, mentor senior engineers, and turn what you know into frameworks and documentation other teams can use without you in the room
Drive engineering process and tooling improvements that span multiple squads, not just your own
Interview and calibrate against our career ladder, giving honest, evidence-based assessments of candidates
Use AI agents to make multi-file changes by scoping the work, writing the prompt, and verifying the output

10+ years building scalable, distributed systems in Go (or similar statically typed languages), including several as the person others turned to on architecture
Depth across multiple systems or domains, not just one — you've been the recognized expert in more than one place
A track record of designing for production reality: you quantify tradeoffs in throughput, cost, and reliability rather than picking a reasonable path and defending it
Experience designing observability and recovery as first-class concerns — metrics, alerting, rollback, backpressure, checkpointing — not logging added afterward
Comfort working in cloud-native environments (AWS, GCP), with relational databases (we use MySQL) and a real understanding of performance tradeoffs
Evidence of making other engineers better: mentorship, technical writing, design review, standards that outlasted your involvement
A bias for action over perfection, and the judgment to know which decisions are worth slowing down for