App settings reference for Azure Functions

App settings in a function app contain configuration options that affect all functions for that function app. When you run locally, these settings are accessed as local environment variables. This article lists the app settings that are available in function apps.

There are several ways that you can add, update, and delete function app settings:

Changes to function app settings require your function app to be restarted.

There are other function app configuration options in the host.json file and in the local.settings.json file. Example connection string values are truncated for readability.


You can use application settings to override host.json setting values without having to change the host.json file itself. This is helpful for scenarios where you need to configure or modify specific host.json settings for a specific environment. This also lets you change host.json settings without having to republish your project. To learn more, see the host.json reference article. Changes to function app settings require your function app to be restarted.


The instrumentation key for Application Insights. Only use one of APPINSIGHTS_INSTRUMENTATIONKEY or APPLICATIONINSIGHTS_CONNECTION_STRING. When Application Insights runs in a sovereign cloud, use APPLICATIONINSIGHTS_CONNECTION_STRING. For more information, see How to configure monitoring for Azure Functions.

Key Sample value
APPINSIGHTS_INSTRUMENTATIONKEY 55555555-af77-484b-9032-64f83bb83bb


The connection string for Application Insights. Use APPLICATIONINSIGHTS_CONNECTION_STRING instead of APPINSIGHTS_INSTRUMENTATIONKEY in the following cases:

  • When your function app requires the added customizations supported by using the connection string.
  • When your Application Insights instance runs in a sovereign cloud, which requires a custom endpoint.

For more information, see Connection strings.

Key Sample value


By default, Functions proxies use a shortcut to send API calls from proxies directly to functions in the same function app. This shortcut is used instead of creating a new HTTP request. This setting allows you to disable that shortcut behavior.

Key Value Description
AZURE_FUNCTION_PROXY_DISABLE_LOCAL_CALL true Calls with a backend URL pointing to a function in the local function app won't be sent directly to the function. Instead, the requests are directed back to the HTTP frontend for the function app.
AZURE_FUNCTION_PROXY_DISABLE_LOCAL_CALL false Calls with a backend URL pointing to a function in the local function app are forwarded directly to the function. This is the default value.


This setting controls whether the characters %2F are decoded as slashes in route parameters when they are inserted into the backend URL.

Key Value Description
AZURE_FUNCTION_PROXY_BACKEND_URL_DECODE_SLASHES true Route parameters with encoded slashes are decoded.
AZURE_FUNCTION_PROXY_BACKEND_URL_DECODE_SLASHES false All route parameters are passed along unchanged, which is the default behavior.

For example, consider the proxies.json file for a function app at the domain.

    "$schema": "",
    "proxies": {
        "root": {
            "matchCondition": {
                "route": "/{*all}"
            "backendUri": "{all}"

When AZURE_FUNCTION_PROXY_BACKEND_URL_DECODE_SLASHES is set to true, the URL resolves to By default, the URL remains unchanged as For more information, see Functions proxies.


In version 2.x and later versions of the Functions runtime, configures app behavior based on the runtime environment. This value is read during initialization, and can be set to any value. Only the values of Development, Staging, and Production are honored by the runtime. When this application setting isn't present when running in Azure, the environment is assumed to be Production. Use this setting instead of ASPNETCORE_ENVIRONMENT if you need to change the runtime environment in Azure to something other than Production. The Azure Functions Core Tools set AZURE_FUNCTIONS_ENVIRONMENT to Development when running on a local computer, and this can't be overridden in the local.settings.json file. To learn more, see Environment-based Startup class and methods.


In version 2.x and later versions of the Functions runtime, application settings can override host.json settings in the current environment. These overrides are expressed as application settings named AzureFunctionsJobHost__path__to__setting. For more information, see Override host.json values.


Optional storage account connection string for storing logs and displaying them in the Monitor tab in the portal. This setting is only valid for apps that target version 1.x of the Azure Functions runtime. The storage account must be a general-purpose one that supports blobs, queues, and tables. To learn more, see Storage account requirements.

Key Sample value
AzureWebJobsDashboard DefaultEndpointsProtocol=https;AccountName=...


For better performance and experience, runtime version 2.x and later versions use APPINSIGHTS_INSTRUMENTATIONKEY and App Insights for monitoring instead of AzureWebJobsDashboard.


true means disable the default landing page that is shown for the root URL of a function app. Default is false.

Key Sample value
AzureWebJobsDisableHomepage true

When this app setting is omitted or set to false, a page similar to the following example is displayed in response to the URL <functionappname>

Function app landing page


true means use Release mode when compiling .NET code; false means use Debug mode. Default is true.

Key Sample value
AzureWebJobsDotNetReleaseCompilation true


A comma-delimited list of beta features to enable. Beta features enabled by these flags are not production ready, but can be enabled for experimental use before they go live.

Key Sample value
AzureWebJobsFeatureFlags feature1,feature2


Specifies the repository or provider to use for key storage. Currently, the supported repositories are blob storage ("Blob") and the local file system ("Files"). The default is blob in version 2 and file system in version 1.

Key Sample value
AzureWebJobsSecretStorageType Files


The Azure Functions runtime uses this storage account connection string for normal operation. Some uses of this storage account include key management, timer trigger management, and Event Hubs checkpoints. The storage account must be a general-purpose one that supports blobs, queues, and tables. See Storage account and Storage account requirements.

Key Sample value
AzureWebJobsStorage DefaultEndpointsProtocol=https;AccountName=...


Path to the compiler used for TypeScript. Allows you to override the default if you need to.

Key Sample value
AzureWebJobs_TypeScriptPath %HOME%\typescript


Sets the shared memory size (in bytes) when the Python worker is using shared memory. To learn more, see Shared memory.

Key Sample value

The value above sets a shared memory size of ~256 MB.



Dictates whether editing in the Azure portal is enabled. Valid values are "readwrite" and "readonly".

Key Sample value


The version of the Functions runtime that hosts your function app. A tilde (~) with major version means use the latest version of that major version (for example, "~3"). When new versions for the same major version are available, they are automatically installed in the function app. To pin the app to a specific version, use the full version number (for example, "3.0.12345"). Default is "~3". A value of ~1 pins your app to version 1.x of the runtime. For more information, see Azure Functions runtime versions overview. A value of ~4 lets you run a preview version Azure Functions to use the .NET 6.0 preview. To learn more, see the Azure Functions v4 early preview page.

Key Sample value


This setting enables your function app to run in a version 2.x compatible mode on the version 3.x runtime. Use this setting only if encountering issues when upgrading your function app from version 2.x to 3.x of the runtime.


This setting is intended only as a short-term workaround while you update your app to run correctly on version 3.x. This setting is supported as long as the 2.x runtime is supported. If you encounter issues that prevent your app from running on version 3.x without using this setting, please report your issue.

Requires that FUNCTIONS_EXTENSION_VERSION be set to ~3.

Key Sample value


Specifies the maximum number of language worker processes, with a default value of 1. The maximum value allowed is 10. Function invocations are evenly distributed among language worker processes. Language worker processes are spawned every 10 seconds until the count set by FUNCTIONS_WORKER_PROCESS_COUNT is reached. Using multiple language worker processes is not the same as scaling. Consider using this setting when your workload has a mix of CPU-bound and I/O-bound invocations. This setting applies to all non-.NET languages.

Key Sample value


The language worker runtime to load in the function app. This corresponds to the language being used in your application (for example, dotnet). Starting with version 2.x of the Azure Functions runtime, a given function app can only support a single language.

Key Sample value

Valid values:

Value Language
dotnet C# (class library)
C# (script)
dotnet-isolated C# (isolated process)
java Java
node JavaScript
powershell PowerShell
python Python


This setting enables the Python worker to use shared memory to improve throughput. Enable shared memory when your Python function app is hitting memory bottlenecks.

Key Sample value

With this setting enabled, you can use the DOCKER_SHM_SIZE setting to set the shared memory size. To learn more, see Shared memory.


Controls the managed dependencies background update period for PowerShell function apps, with a default value of 7.00:00:00 (weekly).

Each PowerShell worker process initiates checking for module upgrades on the PowerShell Gallery on process start and every MDMaxBackgroundUpgradePeriod after that. When a new module version is available in the PowerShell Gallery, it's installed to the file system and made available to PowerShell workers. Decreasing this value lets your function app get newer module versions sooner, but it also increases the app resource usage (network I/O, CPU, storage). Increasing this value decreases the app's resource usage, but it may also delay delivering new module versions to your app.

Key Sample value
MDMaxBackgroundUpgradePeriod 7.00:00:00

To learn more, see Dependency management.


Specifies how often each PowerShell worker checks whether managed dependency upgrades have been installed. The default frequency is 01:00:00 (hourly).

After new module versions are installed to the file system, every PowerShell worker process must be restarted. Restarting PowerShell workers affects your app availability as it can interrupt current function execution. Until all PowerShell worker processes are restarted, function invocations may use either the old or the new module versions. Restarting all PowerShell workers completes within MDNewSnapshotCheckPeriod.

Within every MDNewSnapshotCheckPeriod, the PowerShell worker checks whether or not managed dependency upgrades have been installed. When upgrades have been installed, a restart is initiated. Increasing this value decreases the frequency of interruptions because of restarts. However, the increase might also increase the time during which function invocations could use either the old or the new module versions, non-deterministically.

Key Sample value
MDNewSnapshotCheckPeriod 01:00:00

To learn more, see Dependency management.


The period of time after a previous managed dependency upgrade check before another upgrade check is started, with a default of 1.00:00:00 (daily).

To avoid excessive module upgrades on frequent Worker restarts, checking for module upgrades isn't performed when any worker has already initiated that check in the last MDMinBackgroundUpgradePeriod.

Key Sample value
MDMinBackgroundUpgradePeriod 1.00:00:00

To learn more, see Dependency management.


The value for this setting indicates a custom package index URL for Python apps. Use this setting when you need to run a remote build using custom dependencies that are found in an extra package index.

Key Sample value
PIP_EXTRA_INDEX_URL http://my.custom.package.repo/simple

To learn more, see Custom dependencies in the Python developer reference.


The configuration is specific to Python function apps. It defines the prioritization of module loading order. When your Python function apps face issues related to module collision (e.g. when you're using protobuf, tensorflow, or grpcio in your project), configuring this app setting to 1 should resolve your issue. By default, this value is set to 0. This flag is currently in Preview.

Key Value Description
PYTHON_ISOLATE_WORKER_DEPENDENCIES 0 Prioritize loading the Python libraries from internal Python worker's dependencies. Third-party libraries defined in requirements.txt may be shadowed.
PYTHON_ISOLATE_WORKER_DEPENDENCIES 1 Prioritize loading the Python libraries from application's package defined in requirements.txt. This prevents your libraries from colliding with internal Python worker's libraries.


The configuration is specific to Python function apps. Setting this to 1 allows the worker to load in Python worker extensions defined in requirements.txt. It enables your function app to access new features provided by third-party packages. It may also change the behavior of function load and invocation in your app. Please ensure the extension you choose is trustworthy as you bear the risk of using it. Azure Functions gives no express warranties to any extensions. For how to use an extension, please visit the extension's manual page or readme doc. By default, this value sets to 0.

Key Value Description
PYTHON_ENABLE_WORKER_EXTENSIONS 0 Disable any Python worker extension.
PYTHON_ENABLE_WORKER_EXTENSIONS 1 Allow Python worker to load extensions from requirements.txt.


Specifies the maximum number of threads that a Python language worker would use to execute function invocations, with a default value of 1 for Python version 3.8 and below. For Python version 3.9 and above, the value is set to None. Note that this setting does not guarantee the number of threads that would be set during executions. The setting allows Python to expand the number of threads to the specified value. The setting only applies to Python functions apps. Additionally, the setting applies to synchronous functions invocation and not for coroutines.

Key Sample value Max value


This setting is currently in preview.

This setting controls logging from the Azure Functions scale controller. For more information, see Scale controller logs.

Key Sample value

The value for this key is supplied in the format <DESTINATION>:<VERBOSITY>, which is defined as follows:

Property Description
<DESTINATION> The destination to which logs are sent. Valid values are AppInsights and Blob.
When you use AppInsights, make sure Application Insights is enabled in your function app.
When you set the destination to Blob, logs are created in a blob container named azure-functions-scale-controller in the default storage account set in the AzureWebJobsStorage application setting.
<VERBOSITY> Specifies the level of logging. Supported values are None, Warning, and Verbose.
When set to Verbose, the scale controller logs a reason for every change in the worker count, as well as information about the triggers that factor into those decisions. Verbose logs include trigger warnings and the hashes used by the triggers before and after the scale controller runs.


Keep in mind that while you leave scale controller logging enabled, it impacts the potential costs of monitoring your function app. Consider enabling logging until you have collected enough data to understand how the scale controller is behaving, and then disabling it.


Controls the timeout, in seconds, when connected to streaming logs. The default value is 7200 (2 hours).

Key Sample value

The above sample value of 1800 sets a timeout of 30 minutes. To learn more, see Enable streaming logs.


Connection string for storage account where the function app code and configuration are stored in event-driven scaling plans running on Windows. For more information, see Create a function app.

Key Sample value

Only used when deploying to a Premium plan or to a Consumption plan running on Windows. Not supported for Consumptions plans running Linux. Changing or removing this setting may cause your function app to not start. To learn more, see this troubleshooting article.


A value of 1 enables your function app to scale when you have your storage account restricted to a virtual network. You should enable this setting when restricting your storage account to a virtual network. To learn more, see Restrict your storage account to a virtual network.

Key Sample value

Supported on Premium and Dedicated (App Service) plans (Standard and higher). Not supported when running on a Consumption plan.


The file path to the function app code and configuration in an event-driven scaling plan on Windows. Used with WEBSITE_CONTENTAZUREFILECONNECTIONSTRING. Default is a unique string that begins with the function app name. See Create a function app.

Key Sample value
WEBSITE_CONTENTSHARE functionapp091999e2

Only used when deploying to a Premium plan or to a Consumption plan running on Windows. Not supported for Consumptions plans running Linux. Changing or removing this setting may cause your function app to not start. To learn more, see this troubleshooting article.

When using an Azure Resource Manager template to create a function app during deployment, don't include WEBSITE_CONTENTSHARE in the template. This slot setting is generated during deployment. To learn more, see Automate resource deployment for your function app.


Sets the DNS server used by an app when resolving IP addresses. This setting is often required when using certain networking functionality, such as Azure DNS private zones and private endpoints.

Key Sample value


Controls whether Brotli encoding is used for compression instead of the default gzip compression. When WEBSITE_ENABLE_BROTLI_ENCODING is set to 1, Brotli encoding is used; otherwise gzip encoding is used.


The maximum number of instances that the app can scale out to. Default is no limit.


This setting is in preview. An app property for function max scale out has been added and is the recommended way to limit scale out.

Key Sample value


Windows only. Sets the version of Node.js to use when running your function app on Windows. You should use a tilde (~) to have the runtime use the latest available version of the targeted major version. For example, when set to ~10, the latest version of Node.js 10 is used. When a major version is targeted with a tilde, you don't have to manually update the minor version.

Key Sample value


Enables your function app to run from a mounted package file.

Key Sample value

Valid values are either a URL that resolves to the location of a deployment package file, or 1. When set to 1, the package must be in the d:\home\data\SitePackages folder. When using zip deployment with this setting, the package is automatically uploaded to this location. In preview, this setting was named WEBSITE_RUN_FROM_ZIP. For more information, see Run your functions from a package file.


Allows you to set the timezone for your function app.

Key OS Sample value
WEBSITE_TIME_ZONE Windows Eastern Standard Time
WEBSITE_TIME_ZONE Linux America/New_York

The default time zone used with the CRON expressions is Coordinated Universal Time (UTC). To have your CRON expression based on another time zone, create an app setting for your function app named WEBSITE_TIME_ZONE.

The value of this setting depends on the operating system and plan on which your function app runs.

Operating system Plan Value
Windows All Set the value to the name of the desired time zone as given by the second line from each pair given by the Windows command tzutil.exe /L
Linux Premium
Set the value to the name of the desired time zone as shown in the tz database.


WEBSITE_TIME_ZONE is not currently supported on the Linux Consumption plan.

For example, Eastern Time in the US (represented by Eastern Standard Time (Windows) or America/New_York (Linux)) currently uses UTC-05:00 during standard time and UTC-04:00 during daylight time. To have a timer trigger fire at 10:00 AM Eastern Time every day, create an app setting for your function app named WEBSITE_TIME_ZONE, set the value to Eastern Standard Time (Windows) or America/New_York (Linux), and then use the following NCRONTAB expression:

"0 0 10 * * *"

When you use WEBSITE_TIME_ZONE the time is adjusted for time changes in the specific timezone, including daylight saving time and changes in standard time.


Indicates whether all outbound traffic from the app is routed through the virtual network. A setting value of 1 indicates that all traffic is routed through the virtual network. You need this setting when using features of Regional virtual network integration. It's also used when a virtual network NAT gateway is used to define a static outbound IP address.

Key Sample value

Next steps

Learn how to update app settings

See configuration settings in the host.json file

See other app settings for App Service apps