Skip to contentSkip to navigationSkip to topbar
Rate this page:
On this page

Functions and Assets Node.js v18 Upgrade

What do you need to know?

what-do-you-need-to-know page anchor

We are keeping your runtime up to date in accordance with industry standards. Based on the Node.js support schedule(link takes you to an external page), Node.js v16 is no longer in Maintenance long-term support (LTS). Production applications should only use releases of Node.js that are Active LTS or Maintenance LTS.

What do you need to do?

what-do-you-need-to-do page anchor

Re-deploy and test your Functions on the Node.js v18 runtime before February 1st, 2024. A deployment will be required to make your Functions run on the new version of Node.js.

After February 1st, 2024, if you make changes to your Functions, they will need to be deployed on Node.js v18.

Currently, the Node.js version will only change if you explicitly set it via either the UI dropdown in the Dependencies tab, by passing runtime when using the Serverless Toolkit, or by explicitly setting the runtime parameter when creating a Build.

What happens if I do nothing?

what-happens-if-i-do-nothing page anchor

Your currently deployed Functions will continue to execute on the existing Node.js v16 runtime if no changes are made.

  • After February 1st, 2024, if you create a new Service or deploy a Service that has not yet been deployed, it will use Node.js v18 by default.
  • If you have an existing build of a Service deployed, it will continue to use the previously set runtime. After February 1st, 2024, any new deployments must be made on Node.js v18; you will not be able to create any new deployments using Node.js v16.
  • If a Service contains only Assets, then the default Node.js runtime will be used automatically for builds (regardless of the runtime parameter that is sent as part of the Build request). After February 1st, 2024, the default runtime will be Node.js v18.


We encourage all customers to upgrade to Node.js v18, even if you are not planning on making any other changes to your Functions.

How do I upgrade to Node.js v18?

how-do-i-upgrade-to-nodejs-v18 page anchor

Follow the instructions below to upgrade, test, and deploy your code on Node.js v18 before the February 1st, 2024 deadline.



While there are no syntax changes required for the upgrade from Node.js v16 to v18, a possible area of impact is your Service's NPM dependencies. It is important to check that the dependencies you include are supported on Node.js v18.

Using the Functions Editor UI

using-the-functions-editor-ui page anchor

If you have built your application with the latest Functions Editor(link takes you to an external page), you can update your Node.js runtime by following these steps:

  1. Open the Dependencies tab of an existing Service that you wish to update.
  2. Open the Node Version dropdown menu, and select Node v18 .
  3. Click the Deploy All button to build and deploy your Service. Once complete, all Functions within that Service will be running on Node.js v18.

Using the Serverless API

using-the-serverless-api page anchor

If you are using the Serverless API to build and deploy your Services, you can update your Node.js runtime by creating a new Build of your Service with the runtime parameter set to node18.

Using the Twilio CLI and your own Service SID, the command will be:

twilio api:serverless:v1:services:builds:create \
--runtime node18

If you'd prefer to use an SDK to trigger this build, refer to the Build documentation for examples of how to trigger a build in every supported programming language.

Using the Serverless Toolkit

using-the-serverless-toolkit page anchor


Some Serverless Toolkit components depend on 3rd party libraries. These dependencies can be updated by their creators to support Node.js v18 without prior notice. We encourage all customers to upgrade to Node.js v18, even if you are not planning on making any other changes to your Functions.



To avoid unexpected side effects when trying out Node.js v18 make sure to follow these exact steps. Learn more about the possible side effects.

Validate you are on the correct Serverless Toolkit version

validate-you-are-on-the-correct-serverless-toolkit-version page anchor

You should be using @twilio-labs/plugin-serverless version 3.1.0 or newer. You can run twilio plugins to verify your version.

If your version of the Serverless Toolkit does not meet these requirements, you may upgrade to the latest version using the following commands:

twilio plugins:remove @twilio-labs/plugin-serverless
twilio plugins:install @twilio-labs/plugin-serverless@latest

Define your baseline Node.js version

define-your-baseline-nodejs-version page anchor

Open the .twilioserverlessrc configuration file at the root of your project and make sure it includes:

"runtime": "node18"

This will ensure that if you don't declare a specific Node.js runtime it will always use Node.js v16 to ensure that you are not accidentally switching to Node.js v18 before verifying it.

If you are working with multiple people or deploying as part of your CI/CD system, make sure that everyone in your team has the updated .twilioserverlessrc file, for example by pushing it to your version control system.

Create your first deployment with Node.js v18

create-your-first-deployment-with-nodejs-v18 page anchor

To trigger a new deployment with Node.js v18 you can use the --runtime flag. Ideally deploy to a new environment, so you can verify the functionality in isolation.

The deployment command will be:

twilio serverless:deploy --runtime node18 --environment verify-18

Your Functions will now be deployed and running on the Node.js v18 runtime in that environment.

Finalize your Node.js v18 transition

finalize-your-nodejs-v18-transition page anchor

Once you have verified your code with Node.js v18, you can update the .twilioserverlessrc file to use node18 as the runtime.

"runtime": "node18"

That means any future deployments will use Node.js v18 even if you don't pass in the specific runtime using the --runtime flag.

How do I verify that the upgrade was successful?

how-do-i-verify-that-the-upgrade-was-successful page anchor

Your runtime version of Node.js is exposed on the process.version variable, so creating, deploying, and calling a short Function like this will return the current version for verification purposes:

exports.handler = (context, event, callback) => {
return callback(null, process.version);

What if I'm still using Functions(Classic)?

what-if-im-still-using-functionsclassic page anchor

The simplest way to upgrade is to start by using the new Functions editor.

  1. Create a new Service in the New Functions editor(link takes you to an external page) .
  2. Copy your Functions code into the new Service as new Functions.
  3. Copy over any Environment Variables and/or Dependencies that your Function(s) use.
  4. Deploy your new Functions by clicking Deploy All . After February 1st, 2024, your code will be deployed using Node.js v18 by default.
  5. If you wish to test with Node.js v18, you can do so by navigating to the Dependencies tab, selecting Node v18 from the Node Version dropdown, and clicking Deploy All for the change to take effect.
  6. Test that your Functions work as expected in the new Service. Once confident, you can switch your Functions to use Node.js v18.

Be sure to update any references to your old Function (e.g. Studio Flows, Twilio number config) to use the new Function URL. You can copy your new Function URL by clicking Copy URL at the bottom right of the Function editor.



If you would like to change the Node.js runtime within Functions(Classic)(link takes you to an external page), please reach out to support with your Account SID and request that they change the Node.js runtime for you.

If you are using the API directly or the Serverless Toolkit, you might encounter possible side effects if you don't explicitly specify a runtime with each deployment.

By default, if you are not specifying a runtime when creating a Build the API will use the runtime you used for the last successful Build. That means if you successfully deployed your code with Node.js v18 once, any subsequent deployments that don't specify a specific runtime will automatically use Node.js v18 going forward.

To avoid these side effects:

  • With the API: Always pass a runtime parameter when creating a Build
  • With the Serverless Toolkit: Make sure to follow the steps outlined above , especially defining a default runtime in the .twilioserverlessrc file.

Rate this page: