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What is WCF reliability and message delivery guarantees?

Updated May 6, 2026

Short answer

WCF reliability ensures messages are delivered exactly once or at least once.

Deep explanation

Reliable sessions in WCF guarantee message delivery using WS-ReliableMessaging protocol, ensuring no message loss or duplication.

Real-world example

Financial transaction systems ensuring no lost messages.

Common mistakes

  • Enabling reliability without understanding performance impact.

Follow-up questions

  • Does reliability affect performance?
  • What is at-most-once delivery?

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