Backend Engineer (MTA) – Core Sending

About the role

Resend is building a modern email sending platform for developers. As a Backend Engineer on the Core Sending squad, you will design, build, and operate the high‑volume email transport infrastructure that powers transactional and marketing email delivery.

Key responsibilities

• Develop and maintain SMTP delivery, MTA systems, routing, retries, back‑off strategies, and delivery controls.
• Design throttling mechanisms at domain, provider, customer, and IP levels.
• Build infrastructure for shared IP pools, dedicated IPs, warm‑up execution, and reputation‑aware routing.
• Improve classification of bounces, deferrals, transient and hard failures.
• Create debugging tools for delivery issues across customers, domains, providers, routes, IPs, and message types.
• Translate reputation strategy into backend systems and partner with Trust & Safety to protect the sending network.
• Participate in incident response and be on‑call for critical services.

Required profile

• Strong backend engineering experience, preferably with high‑volume delivery systems.
• Understanding of queues, workers, retries, idempotency, rate limits, backpressure, and distributed systems.
• Interest or experience with SMTP, MTAs, DNS, email bounces, deferrals, and IP pool management.
• Focus on reliability, observability, and operational excellence.
• Low ego, high ownership, and a preference for simple, maintainable solutions.

Required skills

• Typescript
• Go (Golang)
• AWS
• PostgreSQL
• Datadog
• SMTP / MTA concepts
• DNS
• Queue and worker architectures
• Distributed system design

What we offer

• Fully remote work with flexible schedules.
• Autonomy to ship features quickly.
• Modern tech stack (Typescript, Go, AWS, Postgres, Datadog).
• Collaborative, low‑ego team culture.
• Competitive compensation: $150k‑$170k USD per year.