resend - Backend Engineer (MTA), Core Sending

• 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 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 • Have strong backend engineering experience • Have worked on email, messaging, notifications, communications, infrastructure, or other high-volume delivery systems • Understand queues, workers, retries, idempotency, rate limits, backpressure, and distributed systems • Have 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 • Have low ego, high ownership, and strong taste for simple systems • YOU WILL BE AN EXCEPTIONAL FIT IF YOU ALSO... • Have experience working on applications with a high workload • Know about email best practices, or are willing to learn more about this space • Are experienced in Typescript and Golang • WHAT IT MEANS TO JOIN THE TEAM: • 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 • Comp: $150,000 - $170,000 USD, commensurate with experience