Clarification on Azure Functions update from Node.js 20 to 22

Hi nchr1998,

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Moving from Node.js 20 to 22 on Azure Functions is totally doable and relatively straightforward since both versions already run on the Azure Functions v4 runtime.

Here’s how to put that into practice:

1. Update the Node.js version to 22

Depending on your hosting OS, the setting you need to update differs:

If you’re on Windows:

• In the Azure Portal: Go to your Function App > Settings > Configuration > General settings > Stack settings and select Node.js 22 from the dropdown.
• Via App Settings / Azure CLI: Set the WEBSITE_NODE_DEFAULT_VERSION app setting to ~22.

      az functionapp config appsettings set \
        --name <APP_NAME> \
        --resource-group <RG_NAME> \
        --settings WEBSITE_NODE_DEFAULT_VERSION=~22
  

If you’re on Linux:

• In the Azure Portal: Go to your Function App > Settings > Configuration > General settings > Stack settings and select Node.js 22.
• Via Azure CLI: Update the linuxFxVersion site config property to "node|22".

      az functionapp config set \
        --name <APP_NAME> \
        --resource-group <RG_NAME> \
        --linux-fx-version "node|22"
  

2. Save & Restart Make sure to save your configuration changes in the portal. The Function App will automatically restart and begin using the new Node.js environment. It's always a best practice to smoke-test this in a staging slot or locally before applying the change directly to your production app.

A few extra tips:

• Programming Model: If you are still using the v3 Node.js Programming Model (how your JavaScript/TypeScript code is structured), Node.js 22 will still run it. However, it's highly recommended to upgrade to the v4 Programming Model (the @azure/functions npm package v4) if you haven't already.
• Linux Consumption Plan Note: Keep in mind that Node.js 22 is the last Node.js version supported for Linux Consumption plan apps. If you plan to upgrade to Node.js 24 or newer in the future, you will eventually need to migrate your app to the newer Flex Consumption plan.

Reference docs:

• Azure Functions Node.js developer guide: https://learn.microsoft.com/azure/azure-functions/functions-reference-node?tabs=v4#setting-the-node-version
• Supported Languages and end-of-support dates: https://learn.microsoft.com/en-us/azure/azure-functions/functions-versions#languages Note: This response is drafted with the help of AI systems.

Updating only the Stack settings → Version to Node.js 22 is not sufficient by itself for a fully supported configuration. For Node.js 22, the app must use the Node.js programming model v4 with the corresponding package/runtime versions.

From the documentation:

• Programming model 4.x (GA) requires:
  • Azure Functions runtime: 4.25+
  • Node.js: 22.x, 20.x, 18.x
• Programming model 3.x (GA) supports Node.js 20.x and 18.x, but not 22.x.
• The programming model version is tied to the @azure/functions npm package version.
• v4 requires @azure/functions v4.0.0+ and Node.js v18+.

Therefore, for a production-safe upgrade to Node.js 22:

1. Confirm the runtime and model requirements
   • Ensure the Function App is on Functions runtime v4.25+.
   • Plan to move to the v4 programming model if not already using it.
2. Upgrade to the v4 programming model (JavaScript/TypeScript) At minimum, this involves:
   • Add/upgrade the npm package:

          npm install @azure/functions
     

     Ensure @azure/functions is in the dependencies section of package.json, not devDependencies.
   • Ensure the Node.js version in the app meets v4 requirements (Node.js v18+; for Node 22 specifically, this is satisfied).
   • For v4, define functions in code instead of function.json:
     • Move trigger/binding configuration from function.json into JavaScript/TypeScript using the app object (for example, app.http(), app.timer()).
   • Set the app entry point in package.json using the main field (for example, "main": "src/index.js" or a glob like "src/functions/*.js").
   • Adjust handler signatures to the v4 model where the trigger input is the first argument and the context is second and optional (for example, change (context, req) to (req, context) or just (req)).
3. Do not mix v3 and v4 in the same Function App
   • As soon as one v4 function is registered, any v3 functions defined via function.json are ignored.
   • Plan a coordinated migration of all functions in the app to v4 before or together with the Node.js 22 switch.
4. Then change Stack settings → Version to Node.js 22
   • After the codebase is on programming model v4 and dependencies/runtime meet the requirements, updating the stack version to Node.js 22 is the correct and supported step.
   • The fact that a dev function “works” after only changing the stack version does not guarantee it is within the supported matrix; for production, align with the documented support table and v4 requirements.

In summary: for Node.js 22, move the Function App to Node.js programming model v4 (including @azure/functions v4, code-based configuration, and correct entry point), ensure Functions runtime v4.25+, and then update the stack version. Relying solely on changing the stack version in the portal is not sufficient for a fully supported production configuration.

References:

• Migrate to version 4 of the Node.js programming model for Azure Functions (programming-language-javascript)
• Migrate to version 4 of the Node.js programming model for Azure Functions (programming-language-typescript)
• Azure Functions Node.js developer guide (nodejs-model-v4)
• Azure Functions Node.js developer guide (nodejs-model-v3)