midWCF
What is InstanceContextMode in WCF?
Updated May 6, 2026
Short answer
InstanceContextMode defines how service instances are created and managed.
Deep explanation
It has three modes: PerCall (new instance per request), PerSession (same instance per session), and Single (one shared instance for all requests).
Real-world example
Chat applications often use PerSession mode for user continuity.
Common mistakes
- Using Single mode without proper synchronization.
Follow-up questions
- Which mode is most scalable?
- What is the risk of Single mode?