Backend Engineer, MTA

Role overview

A backend engineering position focused on building and operating large-scale message transport infrastructure. The role centers on SMTP, delivery reliability, and reputation-aware routing for a high-volume sending platform serving millions of users. It suits engineers who enjoy deep systems work, incident response, and translating operational strategy into backend code.

Responsibilities

- Build and operate core email transport infrastructure, including SMTP delivery, MTA systems, routing, retries, backoff strategies, and delivery controls. - Design throttling systems at the domain, provider, customer, and IP levels, along with shared IP pools, dedicated IPs, warmup execution, and reputation-aware routing. - Improve classification of bounces, deferrals, transient failures, hard failures, and other delivery outcomes. - Build debugging and observability tooling for investigating delivery issues by customer, domain, mailbox provider, route, IP, message type, and event. - Partner with trust-and-safety and core-sending teams to implement controls that protect the sending network from abuse. - Participate in incident response for sending, provider, and deliverability-sensitive issues, including on-call rotation for critical services.

Requirements

- Strong backend engineering experience, ideally in high-volume messaging, notifications, or communications infrastructure. - Working knowledge of queues, workers, retries, idempotency, rate limits, backpressure, and distributed systems design. - Experience or strong interest in SMTP, MTAs, DNS, bounces, deferrals, IP pools, and mailbox-provider behavior. - A mindset oriented to reliability, observability, operational excellence, and reducing blast radius. - Low ego, high ownership, and a strong taste for simple, maintainable designs.

Nice to have

- Prior exposure to applications handling very high workloads. - Familiarity with email best practices, or a clear willingness to learn the domain deeply. - Production experience with TypeScript and Go.

Benefits and work setup

- Fully remote position with flexible working schedules, ideally based in Americas or European time zones. - Occasional travel expected for team off-sites, conferences, and meetups. - Modern stack including TypeScript, Go, AWS, Postgres, and Datadog. - Compensation range of $150,000 to $170,000 USD, commensurate with experience.