Backend Engineer (MTA), Core Sending

Stack

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 bounces, deferrals, transient failures, hard failures, and delivery outcomes are classified
• ▹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

Requirements

• ▹Strong backend engineering experience
• ▹Experience with email, messaging, notifications, communications, 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, IP pools, and mailbox-provider behavior
• ▹Cares about reliability, observability, operational excellence, and reducing blast radius
• ▹Low ego, high ownership, strong taste for simple systems

Nice to have

• ▹Experience working on high-workload applications
• ▹Knowledge of email best practices, or willingness to learn
• ▹Experience with TypeScript and Go

Soft skills

What we offer

• ▹100% remote team with flexible working schedules
• ▹Autonomy, modern tech stack (TypeScript, AWS, Go, Postgres, Datadog)
• ▹Compensation: $150,000-$170,000 USD, commensurate with experience
• ▹Travel for team offsites, conferences and meetups

About the company

Resend is building the modern email sending platform for developers, used by more than 2 million developers. The fully remote team of 45 spans 13+ countries and is backed by a16z and Y Combinator.