What is a Service Principal and how is it used in automation?

Short answer: Service Principal is a security identity for apps or automation. Used for authentication in scripts, CI/CD pipelines, and service-to-service communication. Example – Azure CLI login: az login --service-principal -u <appId> -p <password> --tenant <tenantId>

Real-world example (ShopNest)

ShopNest on Azure typically uses App Service + SQL Database + Blob Storage + Application Insights for monitoring.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.