Backend Engineer, MTA

Resend is building the most accessible email platform for developers. This role is fully remote-based in Americas or European time zones. The role involves building and operating Resend's email transport infrastructure, including SMTP delivery, MTA systems, routing, retries, and delivery controls.

• 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 by customer, domain, mailbox provider, route, IP, message type, and event
• 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 for sending, provider, and deliverability-sensitive issues
• Be on-call for critical services

• Strong backend engineering experience
• Experience with email, messaging, notifications, communications, infrastructure, or other high-volume delivery systems
• Understanding of 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
• Experience working on applications with a high workload
• Knowledge about email best practices, or willingness to learn
• Experience in Typescript and Golang

• 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