Backend Engineer, MTA

Responsibilities

• 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

Languages