Senior Systems Engineer - Delivery DevOps We're looking for a Senior Systems Engineer on the Delivery team to help build, operate, and scale the platform behind Mailchimp's sending infrastructure. That platform includes our in-house Postfix-based MTA (NeoMTA), the PHP server-agent service that routes campaign and transactional mail to it (MCMTA), and the fleet of AWS-hosted MTA servers that carry the load. This is a hands-on systems and infrastructure role. You'll own the health of the sending fleet end to end, from the Linux hosts and MTA software up through the deployment pipelines, autoscaling, monitoring, and the AWS environments the platform runs on. You'll do well here if you're a self-directed engineer who is comfortable in production and on the command line, enjoys the trade-offs of running a mature, high-throughput platform, and thinks in terms of systems, fleets, and reliability rather than single applications. You should understand enough of the deliverability world (reputation, authentication, receiver behavior) to make sound infrastructure decisions, but your center of gravity is systems and cloud engineering. We're looking for a detail-oriented, collaborative communicator who can self-prioritize, so urgent operational issues get handled while longer-term platform work keeps moving. And you're comfortable with AI-native ways of working, using AI and agent tooling to make both yourself and the team more effective. This is an individual-contributor role. It has no direct reports or managerial duties, and your impact comes through your own engineering work and your influence on the team. Responsibilities Systems and Infrastructure Engineering - Design, build, and operate the AWS cloud infrastructure the platform runs on, managing the sending fleet across AWS environments, including AMI and image build pipelines, instance and capacity management, autoscaling, and running the fleet cost-effectively. - Develop and manage Infrastructure-as-Code (for example, Terraform, Ansible, or Puppet) to provision, configure, and maintain scalable, secure server and network environments. - Design and manage system architecture across the sending path, including networking, load balancing, and security configuration, to keep production applications and services healthy. - Design, implement, and maintain the CI/CD pipelines and release automation behind the platform (Jenkins, Artifactory and RPM packaging, containerized services, and Kubernetes/ArgoCD-based delivery), automating deployment workflows so releases to production are reliable, repeatable, and secure. - Configure and maintain containerized environments (Docker, Kubernetes) for application deployment, scaling, and orchestration. - Configure and tune MTA software and host-level parameters to manage throughput, queueing, and delivery behavior across the fleet. Operational Excellence and Reliability - Take part in an on-call rotation, available to handle Delivery-related operational issues outside normal business hours, to keep the platform up and the business running. - Monitor production systems and infrastructure for performance, availability, and security, and own the metrics, dashboards, and alerting that give the team and stakeholders visibility into fleet and sending health (for example, BigQuery, OpenSearch, and Splunk). - Respond to fleet, host, and delivery incidents, diagnosing issues that span the MTA software, the hosts, the AWS environment, and the network. - Write scripts and automation tooling to streamline infrastructure provisioning, system configuration, and operational processes, and to support performance tuning across the fleet. - Take full responsibility for delivering major platform features and projects, managing technical risk, watching them after launch, and keeping stakeholders informed. Platform Health and Deliverability Awareness - Review internal code and configuration changes for their impact on sending infrastructure and reliability. - Build and maintain tooling that tracks sending health and IP and domain reputation, and that supports the team's response to receiver and deliverability trends. - Apply working knowledge of email authentication and receiver behavior (SPF, DKIM, DMARC, feedback loops, and bounce handling) to keep the platform configured correctly and delivering well. Collaboration, AI, and Craft - Partner with Senior and Staff Engineers and Product Managers to analyze infrastructure and reliability requirements, weighing scalability, security, cost, and performance as you design solutions. - Help improve deployment methods, monitoring tools, and infrastructure automation practices across the team. - Look for opportunities to automate operations and improve the platform with AI, and use AI and agent tooling to move faster while owning the quality of whatever those agents produce on your behalf. - Document systems, runbooks, and operational workflows, act as a subject-matter expert, and mentor teammates to raise the whole team's capability. - Communicate clearly and persuasively across global, cross-functional teams and time zones. Qualifications Required - BS/MS in Computer Science or a related field, or equivalent experience - 7+ years of engineering experience, with a strong focus on systems, infrastructure, or platform engineering for large-scale distributed or high-throughput services - Strong Linux administration and Unix command-line skills, including operating and troubleshooting production server fleets - Hands-on experience running production workloads on AWS: compute and instance management, machine images (AMIs), autoscaling, networking, load balancing, and cost-aware operation - Experience with Infrastructure-as-Code and configuration management (for example, Terraform, Ansible, or Puppet) for provisioning and maintaining server and network environments - Experience with CI/CD and delivery automation, including pipelines (for example, Jenkins), artifact and package management, containers (Docker), and orchestration (Kubernetes or similar) - Able to read and write code to build tooling and services; Python and PHP are core to this platform, and Go, C/C++, or Perl are a plus (a sample code or portfolio is welcome) - Experience with MTA software (Postfix, PowerMTA, Momentum, or similar), or comparable experience operating a complex Linux-based server application at scale - Working knowledge of DNS, networking, and email authentication (SPF, DKIM, DMARC) - Experience with relational and in-memory data stores in the serving path (MySQL and Redis; PostgreSQL a plus) - Experience building observability, including metrics, dashboards, and alerting, and comfort with data and analytics tooling (for example, BigQuery, OpenSearch, and Splunk) - Comfortable with Git-based version control and modern development tooling - Comfortable with AI-native ways of working and hands-on with AI and agent tooling in daily engineering work - Able to work independently and as part of a team, break down complex technical concepts for different audiences, and communicate clearly Bonus Points - Experience with in-house or open-source MTA internals (Postfix configuration, queue management, RPM packaging) - Networking depth (TCP/IP, TLS/OpenSSL) and experience diagnosing delivery and connectivity issues at the network layer - Experience with receiver-side anti-abuse processes and resolving deliverability issues with receivers or the anti-abuse community - Python, Regex, and R, plus a math and stats foundation for analyzing sending and reputation data - Familiarity with Jira and Confluence