Backend Engineer, MTA

Role overview A high-volume email platform used by millions of developers is hiring a backend engineer focused specifically on its mail transfer agent (MTA) and email transport infrastructure. The role centers on making sending behavior safer, more observable, and easier to operate as the platform continues to onboard thousands of new users per day. It is fully remote across Americas and European time zones with occasional travel for offsites and conferences.

Responsibilities - Build and operate the platform's email transport infrastructure, including SMTP delivery, MTA systems, routing, retries, backoff, and delivery controls. - Design throttling and rate-limiting systems at the domain, provider, customer, and IP level. - Build infrastructure for shared IP pools, dedicated IPs, warmup execution, and reputation-aware routing. - Improve classification of bounces, deferrals, transient failures, hard failures, and delivery outcomes. - Build debugging tools that surface delivery issues by customer, domain, mailbox provider, route, IP, message type, and event. - Translate reputation strategy into backend systems and partner with trust and safety teams on abuse-prevention controls. - Participate in incident response and on-call rotation for sending-critical and deliverability-sensitive services.

Requirements - Strong backend engineering experience. - Background in email, messaging, notifications, communications infrastructure, or other high-volume delivery systems. - Solid 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. - Care for reliability, observability, operational excellence, and reducing blast radius.

Nice to have - Experience with high-workload applications. - Familiarity with email best practices or willingness to learn. - Proficiency in TypeScript and Go.

Benefits and work setup - 100% remote team with flexible working schedules and autonomy to ship. - Modern tech stack including TypeScript, AWS, Go, Postgres, and Datadog. - Compensation: $150,000 - $170,000 USD, commensurate with experience.