Backend Engineer (MTA), Core Sending

Resend is growing fast, and there are now over 3 million developers using it. As the Core Sending Squad, we are responsible for building and maintaining the core components of Resend that handle sending transactional and marketing emails. This role is fully remote-based in Americas or European time zones, with some expected travel for team off-sites, conferences, meetups, and more. Read more about how we work, how we hire, and what we value here . In this role, you will… • 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 You will be a great fit if you... • 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 About Resend 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. Meet the humans →