Aug. 9, 2025
Most Microsoft 365 automations fail for the same reason: they rely on fragile delegated permissions tied to human users—leading to session timeouts, MFA prompts, role changes, and broken jobs. The fix is shifting to app-only permissions with Microsoft Graph: run headless, least-privilege, auditable automations via a service principal (no user login, no expiring sessions). This guide shows why delegated breaks at scale, how to set up app-only securely (registration, Application permissions, admin consent, Key Vault secrets), and how to extend it with Graph webhooks for real-time, reliable workflows across SharePoint, Teams, and Outlook—without babysitting logins.