Software Engineer II - Inline Mailflow

Abnormal AI is looking for a Software Engineer to join the newly formed Inline Mailflow team. This role involves building the next-generation SMTP relay infrastructure to enhance outbound email security and support a long-term strategy against competitors.

Responsibilities:

• Design and implement core components of the SMTP relay harness, including Mail Transfer Agent (MTA) infrastructure, scalability, IP management, encryption, and DMARC support, working from conception through production operation
• Co-build the production relay alongside existing infra engineers, ramping toward full ownership of defined services as the product matures through Q3 and into EA
• Collaborate with PMs and Solutions Architects to translate customer requirements into reliable, opinionated relay configurations that support inbound and outbound use cases
• Own and operate tier-0 mail flow services that handle high volumes of enterprise email at production SLA, participating in on-call rotations and driving continuous reliability improvements
• Contribute to technical design discussions on how the relay integrates with existing inline products (outbound DLP, behavioral outbound, misdirected email), helping define the architecture of the broader Mail Flow platform
• Raise the bar of engineering excellence by contributing to knowledge sharing, runbooks, and professional development within the team

Requirements:

• BS degree in Computer Science, Applied Sciences, Information Systems, or a related engineering field
• 3+ years of backend software development experience with distributed systems, designing and building production services
• Hands-on experience with our stack: Go and/or Python
• Experience building features and components from scratch and owning them in production, balancing feature development with operational work
• Comfortable with ambiguity and 0-to-1 projects where you help shape requirements alongside product and engineering stakeholders
• Experience working with distributed teams; proficient in asynchronous and written communication
• Solid understanding of email protocols and infrastructure (SMTP, MTA architecture, DNS, SPF/DKIM/DMARC)
• Experience with our extended stack: AWS, Kubernetes, Django, Spark, Prometheus
• Familiarity with email security products or Secure Email Gateways (SEGs) such as Proofpoint, Mimecast, or Microsoft Defender
• Experience with email deliverability concepts: IP reputation, bulk sending infrastructure, bounce handling, or feedback loops
• Familiarity with containerization using Docker or similar technologies