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Functions How To Use Azure Function App Settings
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This page contains Windows bias
About This Page
This page is part of the Azure documentation. It contains code examples and configuration instructions for working with Azure services.
Bias Analysis
Bias Types:
⚠️
windows_first
⚠️
powershell_heavy
⚠️
windows_tools
⚠️
missing_linux_example
Summary:
The documentation demonstrates several forms of Windows bias. Windows and PowerShell tools are consistently presented alongside or before Linux/CLI equivalents, and some features/tools (such as Kudu, App Service Editor, and in-portal console) are either only available on Windows or have limited/no Linux support. Migration instructions and examples are focused on Windows, with explicit notes that migration is not supported on Linux. There are also missing Linux-specific examples or guidance in several sections, and Windows terminology and tools are prioritized throughout.
Recommendations:
- Provide explicit Linux examples and guidance where features are supported, including command-line usage and screenshots.
- Clearly indicate feature parity or lack thereof for Linux in each relevant section, and provide alternative workflows or workarounds for Linux users.
- Avoid presenting Windows/PowerShell instructions first by default; consider parallel presentation or Linux-first ordering where appropriate.
- Expand documentation for Linux-specific deployment, management, and troubleshooting scenarios, including use of SSH-based consoles and Linux-compatible tools.
- Where features are Windows-only, offer links or references to Linux alternatives or explain the roadmap for Linux support.
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Scan History
| Date | Scan ID | Status | Bias Status |
|---|---|---|---|
| 2025-07-12 23:44 | #41 | in_progress | ❌ Biased |
| 2025-07-12 00:58 | #8 | cancelled | ✅ Clean |
| 2025-07-10 05:06 | #7 | processing | ✅ Clean |
Flagged Code Snippets
### [Azure PowerShell](#tab/azure-powershell)
The [`Get-AzFunctionAppSetting`](/powershell/module/az.functions/get-azfunctionappsetting) cmdlet returns the existing application settings, for example:
The [`Update-AzFunctionAppSetting`](/powershell/module/az.functions/update-azfunctionappsetting) command adds or updates an application setting. The following example creates a setting with a key named `CUSTOM_FUNCTION_APP_SETTING` and a value of `12345`:
### [Premium-to-Consumption](#tab/to-consumption/azure-cli)
Use the following procedure to migrate from a Premium plan to a Consumption plan on Windows:
1. Run the [az functionapp create](/cli/azure/functionapp#az-functionapp-create) command as follows to create a new function app (Consumption) in the same region and resource group as your existing function app. This command also creates a new Consumption plan in which the function app runs:
### [Consumption-to-Premium](#tab/to-premium/azure-powershell)
Use the following procedure to migrate from a Consumption plan to a Premium plan on Windows:
1. Run the [New-AzFunctionAppPlan](/powershell/module/az.functions/new-azfunctionappplan) command as follows to create a new App Service plan (Elastic Premium) in the same region and resource group as your existing function app:
1. Run the [Update-AzFunctionApp](/powershell/module/az.functions/update-azfunctionapp) command as follows to migrate the existing function app to the new Premium plan:
1. When you no longer need the Consumption plan originally used by the app, you can run the [Remove-AzFunctionAppPlan](/powershell/module/az.functions/remove-azfunctionappplan) command as follows to delete the Consumption plan you migrated from:
### [Premium-to-Consumption](#tab/to-consumption/azure-powershell)
Use the following procedure to migrate from a Premium plan to a Consumption plan on Windows:
1. Run the [New-AzFunctionApp](/powershell/module/az.functions/new-azfunctionapp) command as follows to create a new function app (Consumption) in the same region and resource group as your existing function app. This command also creates a new Consumption plan in which the function app runs:
1. Run the [Get-AzFunctionApp](/powershell/module/az.functions/get-azfunctionapp) command as follows to get the name of the Consumption plan created with the new function app:
1. Run the [Update-AzFunctionApp](/powershell/module/az.functions/update-azfunctionapp) command as follows to migrate the existing function app to the new Consumption plan:
1. When you no longer need the Consumption plan originally used by the app, you can run the [Remove-AzFunctionAppPlan](/powershell/module/az.functions/remove-azfunctionappplan) command as follows to delete the Consumption plan you migrated from:
---
## Development limitations in the Azure portal
The following table shows the operating systems and languages that support in-portal editing:
| Language | Windows Consumption | Windows Premium | Windows Dedicated | Linux Consumption | Linux Premium | Linux Dedicated |
|-|:-----------------: |:----------------:|:-----------------:|:-----------------:|:-------------:|:---------------:|
| C# | | | | | |
| Java | | | | | | |
| JavaScript (Node.js) |✔|✔|✔| |✔|✔|
| Python | | | |✔ |✔ |✔ |
| PowerShell |✔|✔|✔| | | |
| TypeScript (Node.js) | | | | | | |
Consider these limitations when you develop your functions in the [Azure portal](https://portal.azure.com):
+ In-portal editing is supported only for functions that were created or last modified in the Azure portal.
+ In-portal editing is supported only for JavaScript, PowerShell, Python, and C# Script functions.
+ In-portal editing isn't currently supported by the [Flex Consumption plan](flex-consumption-plan.md#considerations).
+ When you deploy code to a function app from outside the Azure portal, you can no longer edit any of the code for that function app in the portal. In this case, just continue using [local development](functions-develop-local.md).
+ For Python, development with custom modules isn't currently supported in the portal. To add custom modules to your function app, you must [develop your app locally](functions-develop-local.md).
+ For compiled C# functions and Java functions, you can create the function app and related resources in the portal. However, you must create the functions code project locally and then publish it to Azure.
When possible, develop your functions locally and publish your code project to a function app in Azure. For more information, see [Code and test Azure Functions locally](functions-develop-local.md).
## Manually install extensions
C# class library functions can include the NuGet packages for [binding extensions](functions-bindings-register.md) directly in the class library project. For other non-.NET languages and C# script, you should [use extension bundles](extension-bundles.md). If you must manually install extensions, you can do so by [using Azure Functions Core Tools](./functions-core-tools-reference.md#func-extensions-install) locally. If you can't use extension bundles and are only able to work in the portal, you need to use [Advanced Tools (Kudu)](#kudu) to manually create the extensions.csproj file directly in the site. Make sure to first remove the `extensionBundle` element from the *host.json* file.
This same process works for any other file you need to add to your app.
> [!IMPORTANT]
> When possible, don't edit files directly in your function app in Azure. We recommend [downloading your app files locally](deployment-zip-push.md#download-your-function-app-files), using [Core Tools to install extensions](./functions-core-tools-reference.md#func-extensions-install) and other packages, validating your changes, and then [republishing your app using Core Tools](functions-run-local.md#publish) or one of the other [supported deployment methods](functions-deployment-technologies.md#deployment-methods).
The Functions editor built into the Azure portal lets you update your function code and configuration files directly in the portal:
1. Select your function app, then under **Functions**, select **Functions**.
1. Choose your function and select **Code + test** under **Developer**.
1. Choose your file to edit and select **Save** when you finish.
Files in the root of the app, such as function.proj or extensions.csproj need to be created and edited by using the [Advanced Tools (Kudu)](#kudu):
1. Select your function app, expand **Development tools**, and then select **Advanced tools** > **Go**.
1. If prompted, sign in to the Source Control Manager (SCM) site with your Azure credentials.
1. From the **Debug console** menu, choose **CMD**.
1. Navigate to `.\site\wwwroot`, select the plus (**+**) button at the top, and select **New file**.
1. Give the file a name, such as `extensions.csproj`, and then press Enter.
1. Select the edit button next to the new file, add or update code in the file, and then select **Save**.
1. For a project file like *extensions.csproj*, run the following command to rebuild the extensions project:
## Platform features
Function apps run in the Azure App Service platform, which maintains them. As such, your function apps have access to most of the features of Azure's core web hosting platform. When you use the [Azure portal](https://portal.azure.com), the left pane is where you access the many features of the App Service platform that you can use in your function apps.
The following matrix indicates Azure portal feature support by hosting plan and operating system:
| Feature | Consumption plan | Flex Consumption plan | Premium plan | Dedicated plan |
| --- | --- | --- | --- |
| [Advanced tools (Kudu)](#kudu) | Windows: ✔ <br/>Linux: **X** | **X** | ✔ | ✔|
| [App Service editor](#editor) | Windows: ✔ <br/>Linux: **X** | **X** | Windows: ✔ <br/>Linux: **X** | Windows: ✔ <br/>Linux: **X**|
| [Backups](../app-service/manage-backup.md) |**X** |**X** | **X** | ✔|
| [Console](#console) | Windows: command-line <br/>Linux: **X** | **X** | Windows: command-line <br/>Linux: SSH | Windows: command-line <br/>Linux: SSH |
The rest of this article focuses on the following features in the portal that are useful for your function apps:
+ [App Service editor](#editor)
+ [Console](#console)
+ [Advanced tools (Kudu)](#kudu)
+ [Deployment options](#deployment)
+ [CORS](#cors)
+ [Authentication](#auth)
For more information about how to work with App Service settings, see [Configure Azure App Service Settings](../app-service/configure-common.md).
### <a name="editor"></a>App Service editor
The App Service editor is an advanced in-portal editor that you can use to modify JSON configuration files and code files alike. Choosing this option launches a separate browser tab with a basic editor. This editor enables you to integrate with the Git repository, run and debug code, and modify function app settings. This editor provides an enhanced development environment for your functions compared with the built-in function editor.
We recommend that you consider developing your functions on your local computer. When you develop locally and publish to Azure, your project files are read-only in the Azure portal. For more information, see [Code and test Azure Functions locally](functions-develop-local.md).
### <a name="console"></a>Console
The in-portal console is an ideal developer tool when you prefer to interact with your function app from the command line. Common commands include directory and file creation and navigation, as well as executing batch files and scripts.
When developing locally, we recommend using the [Azure Functions Core Tools](functions-run-local.md) and the [Azure CLI].
### <a name="kudu"></a>Advanced tools (Kudu)
The advanced tools for App Service (also known as Kudu) provide access to advanced administrative features of your function app. From Kudu, you manage system information, app settings, environment variables, site extensions, HTTP headers, and server variables. You can also launch **Kudu** by browsing to the SCM endpoint for your function app, for example: `https://<myfunctionapp>.scm.azurewebsites.net/`.
### <a name="deployment"></a>Deployment Center
When you use a source control solution to develop and maintain your functions code, Deployment Center lets you build and deploy from source control. Your project is built and deployed to Azure when you make updates. For more information, see [Deployment technologies in Azure Functions](functions-deployment-technologies.md).
### <a name="cors"></a>Cross-origin resource sharing
To prevent malicious code execution on the client, modern browsers block requests from web applications to resources running in a separate domain. [Cross-origin resource sharing (CORS)](https://developer.mozilla.org/docs/Web/HTTP/CORS) lets an `Access-Control-Allow-Origin` header declare which origins are allowed to call endpoints on your function app.
#### [Azure portal](#tab/azure-portal)
When you configure the **Allowed origins** list for your function app, the `Access-Control-Allow-Origin` header is automatically added to all responses from HTTP endpoints in your function app.
If there's another domain entry, the wildcard (\*) is ignored.
#### [Azure CLI](#tab/azure-cli)
Use the [`az functionapp cors add`](/cli/azure/functionapp/cors#az-functionapp-cors-add) command to add a domain to the allowed origins list. The following example adds the contoso.com domain:
In this example, replace `<APP_NAME>` with your function app name and `<GROUP_NAME>` with the resource group. The returned `URL`, `username`, and `password` columns contain the target URL and credentials for FTPS publishing.
### [Azure PowerShell](#tab/azure-powershell)
Run this Azure PowerShell command that returns the FTPS credentials from the publishing profile.
In the previous example, replace `<RESOURCE_GROUP>` and `<FUNCTION_APP_NAME>` with the resource group and function app names, respectively.
---
## Plan migration
You can migrate a function app between a Consumption plan and a Premium plan on Windows.
>[!TIP]
>We recommend you migrate your Consumption plan app to run in a Flex Consumption plan instead of a Premium plan. This is the only migration option for a Linux Consumption plan app. For more information, see [Migrate Consumption plan apps to the Flex Consumption plan](migration/migrate-plan-consumption-to-flex.md).
When migrating between plans, keep in mind the following considerations:
+ Direct migration to a Dedicated (App Service) plan isn't supported.
+ Migration isn't supported on Linux.
+ The source plan and the target plan must be in the same resource group and geographical region. For more information, see [Move an app to another App Service plan](../app-service/app-service-plan-manage.md#move-an-app-to-another-app-service-plan).
+ The specific CLI commands depend on the direction of the migration.
+ Downtime in your function executions occurs as the function app is migrated between plans.
+ State and other app-specific content is maintained, because the same Azure Files share is used by the app both before and after migration.
You can migrate your plan using these tools:
### [Azure portal](#tab/azure-portal)
You can use the [Azure portal](https://portal.azure.com) to switch to a different plan.
### [Azure CLI](#tab/azure-cli)
You can use the Azure CLI commands to manually create a new plan, switch your app to use the new plan, and delete the original plan.
### [Azure PowerShell](#tab/azure-powershell)
You can use Azure PowerShell commands to manually create a new plan, switch your app to use the new plan, and delete the original plan.
---
Choose the direction of the migration for your app on Windows.
### [Consumption-to-Premium](#tab/to-premium/azure-portal)
1. In the Azure portal, navigate to your Consumption plan app, and in the left pane expand **App Service plan** and select **App Service plan**.
1. In the **App Service plan** page, select **Change plan** under **Current App Service plan**.
1. In **Change App Service plan**, select **Premium** for **Plan type**, create a new Premium plan, and select **OK**.
For more information, see [Move an app to another App Service plan](../app-service/app-service-plan-manage.md#move-an-app-to-another-app-service-plan).
### [Premium-to-Consumption](#tab/to-consumption/azure-portal)
1. In the Azure portal, navigate to your Elastic Premium plan app, and in the left pane expand **App Service plan** and select **App Service plan**.
1. In the **App Service plan** page, select **Change plan** under **Current App Service plan**.
1. In **Change App Service plan**, select **Consumption** under **Plan type**, create a new Consumption plan, and select **OK**.
For more information, see [Move an app to another App Service plan](../app-service/app-service-plan-manage.md#move-an-app-to-another-app-service-plan).
### [Consumption-to-Premium](#tab/to-premium/azure-cli)
Use the following procedure to migrate from a Consumption plan to a Premium plan on Windows:
1. Run the [az functionapp create](/cli/azure/functionapp/plan#az-functionapp-plan-create) command as follows to create a new App Service plan (Elastic Premium) in the same region and resource group as your existing function app: