Backend Engineer, MTA

Lever, Inc.; Germany (OH); Remote; USD 150,000 - 170,000; Full time

Job summary

Lever, Inc. is hiring a Backend Engineer focused on MTAs and high-volume email infrastructure. You will own the delivery stack from SMTP to reputation-aware routing, ensuring reliability and observability across distributed systems.

Work is fully remote with flexible schedules; you will collaborate with Trust & Safety and Core Sending teams, and participate in on-call rotation and incident response.

Qualifications

• Strong backend engineering experience.
• Experience with high-volume delivery systems or messaging infrastructure.
• Familiarity with queues, retries, idempotency, rate limits.
• Interest in SMTP/MTAs and email delivery best practices.

Responsibilities

• Build and operate email transport and delivery infrastructure.
• Develop SMTP delivery, MTA operations, routing, retries, throttling.
• Design throttling across domains, IPs, and providers.
• Own tools for investigating delivery issues and incidents.

Skills

Backend engineering

Distributed systems

Observability

Reliability

TypeScript/Go

Remote work

On-call

Tools

TypeScript

Go

AWS

PostgreSQL

Datadog

Job description

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Backend Engineer, MTA based in Germany.

This is an opportunity to build and operate the backend infrastructure that powers high-volume email delivery at scale. You’ll work on critical systems spanning SMTP delivery, routing, retries, throttling, and delivery controls. The role combines backend engineering with the complexities of distributed systems, email infrastructure, and sender reputation. You’ll help create reliable, observable systems that make sending behavior safer and easier to operate. You’ll collaborate closely with Trust & Safety and Core Sending teams while taking significant ownership of technical problems and solutions. The position is fully remote, with flexible working schedules and occasional travel for team off-sites, conferences, and meetups.

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.