Your Durable Function runs many times

Frequently asked questions

Why does a Durable Functions orchestrator run from the top every time?

The orchestrator replays its entire function body from line one on every checkpoint, but activities that already completed answer instantly from the recorded event history instead of running again — that's how it resumes exactly where it left off without keeping the process alive between awaits.

Why do DateTime.Now and Guid.NewGuid break a Durable Function?

Replay re-executes the same code path multiple times, so any non-deterministic call would return a different value on each replay and desynchronize the orchestrator from its own history. Use the context's deterministic equivalents instead.

Read deeper on Azure

Twenty seconds gets the shape of an idea across. These go into how it behaves in production.

• AI Bot Attacks on a Mobile App Login, and How Azure Stops Them

  A script tries 8,000 passwords a minute against your login API at 3am. Rate limiting, smart lockout and Defender for Cloud make speed the losing move.

• Azure Key Vault Explained: The One Secret Tutorials Never Remove

  Moving every secret into Key Vault leaves exactly one behind: the credential that opens the vault. A managed identity is what removes it.

• How to Secure a Mobile API on Azure in Five Steps, in the Right Order

  HTTPS only, authentication, authorization, secrets and monitoring: five steps to secure a mobile API on Azure, and why the order carries most of the value.