Backend Engineer, MTA

The role

You will build and operate Resend's email transport infrastructure. This includes working on SMTP delivery, MTA systems, routing, and designing throttling and IP pool systems.

What you will do

• Build and operate Resend's email transport infrastructure
• Work on SMTP delivery, MTA systems, routing, retries, backoff strategies, and delivery controls
• Design systems for domain-level, provider-level, customer-level, and IP-level throttling
• Build infrastructure for shared IP pools, dedicated IPs, warmup execution, and reputation-aware routing
• Improve how Resend classifies bounces, deferrals, transient failures, hard failures, and delivery outcomes
• Build tools that help the team debug delivery issues
• Help design systems that make sending behavior safer, more observable, and easier to operate
• Translate reputation strategy into backend systems
• Partner with Trust & Safety and Core Sending to build controls that protect Resend's sending network from abuse
• Participate in incident response and be on-call for critical services

Required qualifications

• Strong backend engineering experience
• Worked on email, messaging, notifications, communications, infrastructure, or other high-volume delivery systems
• Understand queues, workers, retries, idempotency, rate limits, backpressure, and distributed systems
• Experience or strong interest in SMTP, MTAs, DNS, bounces, deferrals, DNS, IP pools, and mailbox-provider behavior
• Care about reliability, observability, operational excellence, and reducing blast radius
• Low ego, high ownership, and strong taste for simple systems

Nice to have

• Experience working on applications with a high workload
• Know about email best practices, or are willing to learn more about this space
• Experienced in Typescript and Golang

Benefits

• Autonomy to "just ship it"
• 100% remote team with flexible working schedules
• Modern tech stack (Typescript, AWS, Go, Postgres, Datadog)
• Honest and low-ego team
• Ownership of problems and solutions

About the company

Resend is building the modern email sending platform for developers. Their fully remote team of 50 spans 15 countries and is backed by a16z, Y Combinator, and others.