Backend Engineer (MTA), Core Sending

Resend

7d•$150,000 - $170,000•Remote

About The Position

Resend is experiencing rapid growth, with over 2 million developers now using the platform. The Core Sending Squad is responsible for developing and maintaining the fundamental components of Resend that manage the sending of transactional and marketing emails. This role is fully remote and requires availability within Americas or European time zones. Occasional travel for team off-sites, conferences, and meetups is expected.

Requirements

Strong backend engineering experience
Experience working on 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

Nice To Haves

Experience working on applications with a high workload
Knowledge of email best practices, or willingness to learn more about this space
Experience in Typescript and Golang

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 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