Backend Engineer, MTA

Accountabilities:: Build, operate, and continuously improve email transport and delivery infrastructure. Develop systems for SMTP delivery, MTA operations, routing, retries, backoff strategies, and delivery controls. Design and maintain throttling mechanisms across domains, providers, customers, and IP addresses. Build infrastructure supporting shared IP pools, dedicated IPs, warmup execution, and reputation-aware routing. Improve the classification and handling of bounces, deferrals, transient failures, hard failures, and other delivery outcomes. Develop internal tools that make delivery issues easier to investigate across customers, domains, mailbox providers, routes, IPs, message types, and events. Design systems that improve the safety, observability, reliability, and operational efficiency of email sending. Translate sender-reputation strategies into robust backend systems and controls. Partner with Trust & Safety and Core Sending teams to protect the sending network from abuse. Participate in incident response for sending, provider, and deliverability-sensitive issues. Take part in on-call responsibilities for critical services. Requirements: Strong professional experience in backend engineering. Experience working with 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 with, or a strong interest in learning about, SMTP, MTAs, DNS, bounces, deferrals, IP pools, and mailbox-provider behavior. Strong focus on reliability, observability, operational excellence, and minimizing the potential impact of incidents. A high level of ownership, low-ego collaboration, and a preference for simple, maintainable systems. Experience building and operating applications with significant workloads. Familiarity with email best practices, or demonstrated willingness to develop expertise in this area. Experience with TypeScript and/or Go is highly valued. Ability to work effectively in a fully remote environment with distributed teammates and flexible schedules. Benefits: Fully remote position with flexible working schedules. Competitive compensation of $150,000–$170,000 USD , depending on experience. Autonomy and ownership to identify problems, develop solutions, and ship improvements. Opportunity to work with a modern technology stack including TypeScript, AWS, Go, PostgreSQL, and Datadog . Collaborative, honest, and low-ego working environment. Meaningful ownership of critical infrastructure and technical decisions. Opportunities to attend team off-sites, conferences, meetups, and other industry events. Opportunity to work on large-scale email infrastructure used by millions of users.