Senior Systems Engineer - Email Deliverability & Infrastructure

About the role

We are looking for a highly technical Senior Systems Engineer to own, scale, and protect our core email transmission infrastructure. The role focuses on maintaining high‑availability MTAs, ensuring flawless DNS and authentication configurations, and defending our IP/domain reputation.

Key responsibilities

• Maintain and configure core MTAs (Postfix, Postal) and IMAP/POP3 servers (Dovecot) with zero‑downtime reloads.
• Design traffic routing and load‑balancing using HAProxy and BGP (FRRouting) for outbound mail.
• Administer PostgreSQL replica setups and backup/archive servers for redundancy.
• Enforce SPF, DKIM, DMARC, and BIMI policies, handling key rotation and lookup limits.
• Implement dynamic throttling, warm‑up plans, and outbound spam filtering with Rspamd.
• Deploy edge defenses such as Fail2Ban and custom SMTP blockers to mitigate abuse.
• Monitor observability stack and respond to incidents to keep mail operations running 24/7.

Required profile

• Senior‑level experience in Linux systems administration and network engineering.
• Deep understanding of email deliverability, reputation management, and authentication protocols.
• Proven ability to design high‑availability, fault‑tolerant infrastructure.

Required skills

• Linux (Ubuntu/CentOS)
• Postfix, Postal, Dovecot
• HAProxy, BGP, FRRouting
• PostgreSQL replication
• SPF, DKIM, DMARC, BIMI
• Rspamd
• Fail2Ban and custom scripting for SMTP blocking
• IP/domain warm‑up strategies