AzureWebJobsStorage 🔷 Azure

Azure Functions: Value cannot be null. (Parameter 'connectionString') / Missing value for AzureWebJobsStorage

A Functions app setting or binding connection string is missing — most often AzureWebJobsStorage locally (local.settings.json) or after a settings change.

Seen on: Azure

Meaning

The Functions host needs storage for triggers (except HTTP-only on some plans). Bindings reference app settings by name (Connection = "ServiceBus"), and a missing setting results in null connection strings.

Common causes

  • AzureWebJobsStorage not set (or empty)
  • local.settings.json missing or not copied
  • Binding Connection name doesn’t match an app setting
  • Identity-based connection settings incomplete (__accountName)

⚡ Quick fix

  1. Set AzureWebJobsStorage (UseDevelopmentStorage=true with Azurite locally)
  2. Make binding Connection names match app settings
  3. For identity-based connections set <name>__accountName / __fullyQualifiedNamespace

Detailed fix by platform

JSON

  1. bash
    {
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "FUNCTIONS_WORKER_RUNTIME": "dotnet-isolated",
    "ServiceBus__fullyQualifiedNamespace": "sb-app.servicebus.windows.net"
  }
}

How to diagnose

  1. Settings — App settings / local.settings.json
  2. Binding — Connection property names

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