Environment Variables
This reference lists key environment and app settings for Azure Functions Node.js v4 applications.
Topic/Command Groups
flowchart TD
A[Settings] --> B[Runtime]
A --> C[Node worker]
A --> D[Observability]
| Variable | Purpose | Typical Value |
FUNCTIONS_WORKER_RUNTIME | Select language worker | node |
FUNCTIONS_EXTENSION_VERSION | Runtime major line | ~4 |
WEBSITE_NODE_DEFAULT_VERSION | Node version on Windows workers only | ~20 |
siteConfig.linuxFxVersion | Node runtime stack on Linux workers | Node|20 |
languageWorkers__node__arguments | Node process flags | --max-old-space-size=4096 |
AzureWebJobsStorage | Host storage connection | Connection string or identity settings |
APPLICATIONINSIGHTS_CONNECTION_STRING | Telemetry ingestion target | <connection-string> |
Apply settings
az functionapp config appsettings set --name $APP_NAME --resource-group $RG --settings "FUNCTIONS_WORKER_RUNTIME=node" "FUNCTIONS_EXTENSION_VERSION=~4" "WEBSITE_NODE_DEFAULT_VERSION=~20" "languageWorkers__node__arguments=--max-old-space-size=4096"
az functionapp config appsettings set --name $APP_NAME --resource-group $RG --settings "FUNCTIONS_WORKER_RUNTIME=node" "FUNCTIONS_EXTENSION_VERSION=~4" "languageWorkers__node__arguments=--max-old-space-size=4096"
az functionapp config set --name $APP_NAME --resource-group $RG --linux-fx-version "Node|20"
| CLI element | Explanation |
| Command(s) | az functionapp config appsettings set, az functionapp config set |
| Key flags | --name, --resource-group, --settings, --max-old-space-size, --linux-fx-version |
| Variables | $APP_NAME, $RG |
| Expected result | Azure CLI applies the configuration change; confirm the returned JSON or follow-up query shows the expected value. |
- Windows apps use
WEBSITE_NODE_DEFAULT_VERSION. - Linux apps use
siteConfig.linuxFxVersion through az functionapp config set --linux-fx-version "Node|20".
Usage Notes
- Keep local values in
local.settings.json and exclude from source control. - Prefer identity-based connections when available.
- Use separate settings per environment (dev, test, prod).
See Also
Sources