Senior Software Engineer

**Overview**



**Substrate** is at the core of Microsoft’s mission to empower every organization on the planet to achieve more. The **Substrate Transport** team builds the global messaging platform that underpins collaboration across Microsoft 365. We own the Exchange Online transport pipeline, processing billions of messages daily—from traditional email to service-to-service communications, enabling secure, reliable delivery across Outlook, SharePoint, Teams, Copilot and emerging M365 experiences.



Substrate Transport is more than an email pipeline - it's a **high-scale, intelligent message processing platform** that is constantly evolving to meet the ever-increasing demands of new M365 experiences, now including Copilot. Small design decisions can have massive impact on user trust, service health, and feature velocity across M365.



We are modernizing the Transport messaging pipeline to increase reliability, serviceability, and...