Create an add-on in any coding language quickstart

Create a Google Workspace Add-on in Cloud Functions without using Apps Script.


  • Set up your environment.
  • Create and deploy a Cloud Function.
  • Create and deploy the add-on.
  • Install the add-on.


Set up your environment

Open your Cloud project in the Google Cloud console

  1. In the Google Cloud console, go to the Select a project page.

    Select a Cloud project

  2. Select the Google Cloud project you want to use. Or, click Create project and follow the on-screen instructions. If you create a Google Cloud project, you might need to turn on billing for the project.

Google Workspace Add-ons require a consent screen configuration. Configuring your add-on's OAuth consent screen defines what Google displays to users.

  1. In the Google Cloud console, go to Menu > APIs & Services > OAuth consent screen.

    Go to OAuth consent screen

  2. Select the user type for your app, then click Create.
  3. Complete the app registration form, then click Save and Continue.
  4. For now, you can skip adding scopes and click Save and Continue. In the future, when you create an app for use outside of your Google Workspace organization, you must add and verify the authorization scopes that your app requires.

  5. If you selected External for user type, add test users:
    1. Under Test users, click Add users.
    2. Enter your email address and any other authorized test users, then click Save and Continue.
  6. Review your app registration summary. To make changes, click Edit. If the app registration looks OK, click Back to Dashboard.

Create and deploy a Cloud Function

  1. In a local terminal, turn on the Cloud Functions, Cloud Build, and the Add-ons API:

    gcloud services enable cloudfunctions
  2. In an empty directory, create the file function.js with the following sample code:

     * Google Cloud Function that loads the homepage for a
     * Google Workspace Add-on.
     * @param {Object} req Request sent from Google
     * @param {Object} res Response to send back
    exports.loadHomePage = function addonsHomePage (req, res) {
    /** Creates a card with two widgets. */
    function createAction() {
      return {
        "action": {
          "navigations": [
              "pushCard": {
                "header": {
                  "title": "Cats!"
                "sections": [
                    "widgets": [
                        "textParagraph": {
                          "text": "Your random cat:"
                        "image": {
                          "imageUrl": ""
  3. Deploy the function:

    gcloud functions deploy loadHomePage --runtime nodejs12 --trigger-http

    If prompted, specify that you do not allow unauthenticated invocations of the function. It might take a couple minutes for the function to deploy.

Create an add-on deployment

  1. Find the service account email for the add-on:

    gcloud workspace-add-ons get-authorization
  2. Grant the service account the cloudfunctions.invoker role:

    gcloud functions add-iam-policy-binding loadHomePage \
        --role roles/cloudfunctions.invoker \
        --member serviceAccount:SERVICE_ACCOUNT_EMAIL
  3. Get the URL of the deployed function:

    gcloud functions describe loadHomePage
  4. Create the file deployment.json with the following sample code. Replace URL with the URL of the deployed function from the previous step.

      "oauthScopes": [""],
      "addOns": {
        "common": {
          "name": "My HTTP Add-on",
          "logoUrl": "",
          "homepageTrigger": {
            "runFunction": "URL"
        "gmail": {},
        "drive": {},
        "calendar": {},
        "docs": {},
        "sheets": {},
        "slides": {}
  5. Create the deployment:

    gcloud workspace-add-ons deployments create quickstart \

Install the add-on

  1. Install the deployment in development mode:

    gcloud workspace-add-ons deployments install quickstart
  2. Open or reload Gmail to view the add-on. In the toolbar on the right, look for a beaker icon.

  3. Click the icon to open the add-on. If prompted, authorize the add-on.

Clean up

  1. Uninstall the add-on from your Google Account:

    gcloud workspace-add-ons deployments uninstall quickstart
  2. To avoid incurring charges for the resources used in this quickstart, delete the project:

    gcloud projects delete PROJECT_ID

    Replace PROJECT_ID with the ID of the project that you used for the quickstart. You can find the project ID in the Cloud console on the Dashboard page.