Senior Software Engineer—Email Channel

Company: Customer.io

Job Category: Software Engineering / Backend

Contract Type: Full-Time, Permanent

Location Eligibility: Remote—Americas

Salary: Competitive (not publicly listed; Customer.io pays market rates for Americas)

Application Link: https://job-boards.greenhouse.io/customerio/jobs/7914033

Application Email: [email protected] Closing Date: Open until filled

About the Company: Customer.io is a leading messaging platform sending billions of communications per day for 8,000+ companies, including startups and global brands. Engineering-led and fully remote.

Job Description: Customer.io is hiring a Senior Software Engineer to work on the Email Channel team — a critical component of the core product. You'll build and improve the infrastructure that powers reliable, scalable, and intelligent email delivery at a massive scale.

Key Responsibilities:

• Design, build, and maintain email delivery infrastructure and integrations with ESP providers
• Improve email reliability, throughput, and deliverability for millions of daily sends
• Work cross-functionally with Product and Design to ship impactful features for email channel customers
• Participate in on-call rotations and handle production incidents
• Contribute to technical direction, code reviews, and engineering culture

Requirements:

• 5+ years of professional software engineering experience
• Strong background in distributed systems and high-throughput data pipelines
• Experience with backend languages such as Go, Ruby, or Python
• Familiarity with email infrastructure: SMTP, ESP integrations, deliverability best practices

Skills Required: Go or Ruby or Python, distributed systems, email infrastructure, API design, system design, async communication

Benefits: Full Customer.io benefits package (medical, dental, vision, PTO, parental leave, remote stipend)