Backend Engineer, MTA

Resend is building the most accessible email platform for developers. As we've grown to 4M+ users and continue to onboard thousands of new users every day, the pressure of maintaining a safe place for good senders continues to build. This role is fully remote-based in Americas or European time zones, with some expected travel for team off-sites, conferences, meetups, and more. We are building the modern email sending platform for developers. We care deeply about quality, craft, and the developer experience. Our fully remote team of 50 spans 15 countries and counting. We're backed by a16z, Y Combinator, and others.

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; Be on-call for critical services

Requirements

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

Nice to have

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

Benefits

Autonomy to "just ship it"; 100% remote team with flexible working schedules; Honest and low-ego team; Ownership of problems and solutions