Senior System Engineer

About the Team
At Trendyol Tech, our mission is to create a positive impact in our ecosystem by enabling commerce through technology.
We solve complex problems with data, creativity, and agility — always driven by real outcomes. With a culture built on learning, collaboration, and ownership, we grow together while building what’s next.
About the Role
In this role, you will be responsible for the architectural design, operational continuity, and evolution of the organization’s Identity and Collaboration platforms, including Active Directory, Windows DNS, Exchange Server (On-Prem & Online), Azure / Entra ID, and Google Workspace.
As a Senior Engineer, you will own hybrid identity architectures end-to-end, managing AD–Azure AD integrations, mail flow dependencies, and authentication flows at a system level. You will ensure high availability and security across Exchange environments (On-Prem, Hybrid, and Online) while deeply managing the impact of Windows DNS and core directory services on critical platforms.

Responsibilities

• Own the design, operation, and continuity of Active Directory, Azure AD (Entra ID), Windows DNS, Exchange (On-Prem & Online), and Google Workspace infrastructures.
• Design scalable, secure, and highly available architectures for email services and provide technical leadership across the end-to-end engineering lifecycle.
• Take ownership of critical incidents within incident, problem, and change management (ITIL) processes; perform root cause analysis (RCA) and deliver permanent fixes.
• Continuously improve identity and email operations through automation, self-service, and standardization approaches.
• Proactively manage risks by considering security, access control, audit, and compliance requirements.
• Design systems in ambiguous or complex scopes; guide technical decisions through risk, dependency, and effort assessments.
• Act as a role model in technical documentation, architectural decisions, and RFC/ADR processes, raising quality and engineering standards.
• Support mentorship and technical growth within the team; promote performance, reliability, and sustainability best practices.
• Balance technical priorities with business needs and customer experience, delivering solutions with measurable business value.
• Ensure clear, structured communication across teams and stakeholders to maintain technical alignment and enable shared decision-making.

Expected Qualifications

• Active Directory (On-Prem) Enterprise-scale AD architecture, multi-domain/forest designs, GPOs, delegation, and replication management.
  
• Windows DNS AD-integrated DNS, forward/reverse zones, conditional forwarders, and advanced troubleshooting of DNS-related identity issues.
  
• Exchange Server (On-Prem & Hybrid) Exchange 2016/2019 architecture, DAG, mail flow, certificate management, and Hybrid Exchange scenarios.
  
• Exchange Online & Microsoft 365 Exchange Online tenant administration, mail flow rules, anti-spam/anti-phishing, DKIM/SPF/DMARC, and compliance policies.
  
• Azure & Azure AD (Microsoft Entra ID) Hybrid identity, Azure AD Connect, Conditional Access, MFA, RBAC, and identity auditing processes.
  
• Google Workspace Tenant, user, group, and access management; Gmail routing, security policies, and AD/Azure AD integrations.
  
• Automation & Scripting PowerShell and script-based automation; provisioning/de-provisioning and self-service implementations.
  
• ITIL / Service Management Strong technical ownership across incident, problem, and change management processes.
  
• Monitoring & Troubleshooting Advanced monitoring, root cause analysis, and performance optimization for identity and email services.