Backend Engineer, MTA

Team: IT

Location: Spain

Commitment: Full-time

Workplace Type: remote

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.