Senior Backend Engineer

Details

Customer.io is used by over 7,500 companies — from scrappy startups to global brands — to send billions of emails, push notifications, in-app messages, and SMS every day. The platform powers automated communication that people actually want to receive. The engineering stack includes Go, React, Ember, and AI to enable rapid shipping and confident scaling. This role focuses on designing, building, and evolving backend systems that power communication at massive scale.

Responsibilities

• 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 short videos, thoughtful writing, and mentorship
• Leverage AI tools to prototype, move faster, and make better decisions

Requirements

• 7+ years of experience building scalable, distributed systems in Go
• Comfort working in cloud-native environments (AWS, GCP)
• Familiarity with relational databases (Customer.io uses 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

• Starting salary for this role: $150,000 - $200,000 USD (or equivalent in local currency) depending on experience and subject to market rate adjustment
• 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
• Professional development budget and other inclusive benefits

Interview Process

• Application review
• Recruiter call (30 mins)
• Behavioral interview (60 mins) covering ownership, product thinking, and collaboration
• Technical interview (60 mins), a collaborative system design conversation focused on scaling challenges
• Take-home assignment (short, realistic task)
• Assignment review call (60 mins)
• Final candidates will complete background checks and employment verifications

Values & Hiring Notes

• Customer.io values ownership, engineers with product taste, and a healthy skepticism for “the way things are done.”
• Zoom is the only video platform used for interviews; virtual interviews use video (not chat).
• Offers will be extended in writing on Customer.io letterhead. For questions, contact [email protected].
• The company is committed to inclusion, equity, and bias-free hiring practices.