Publishing as an Add-on

Once you've developed a useful Apps Script that can benefit others, publishing it as an add-on is the most powerful way to share it. Add-ons integrate seamlessly with Google Workspace applications like Sheets, Docs, Forms, and Gmail, providing a branded and professional user experience. This allows users to install your script directly from the Google Workspace Marketplace and use it within their familiar environment.

The process of publishing an add-on involves several key steps. You'll need to ensure your script is well-structured, adheres to best practices, and provides a clear user interface. It's important to note that publishing an add-on is a more involved process than simply sharing a script or deploying it as a web app. It requires careful consideration of user experience, security, and adherence to Google's policies.

Here's a breakdown of the essential steps and considerations for publishing your Apps Script as an add-on:

1. Prepare Your Script for Add-on Publishing:
   • Define your scope: Determine which Google Workspace applications your add-on will interact with (e.g., Sheets, Docs, Gmail). This will influence the required OAuth scopes.
   • User Interface: Design a user-friendly interface, typically using HTML Service or CardService for interactive elements. For simple add-ons, a custom menu in the host application might suffice.
   • Authorization: Ensure your script clearly requests only the necessary permissions (OAuth scopes) from users. Overly broad scopes can deter users from installing your add-on.
   • Error Handling: Implement robust error handling and provide informative messages to the user.

2. Configure Your Project for Publishing:
   • Project Properties: Set your project's name, description, and icon. These will be displayed in the Google Workspace Marketplace.
   • Deployment ID: You'll need to create a deployment for your script. Go to 'Deploy' > 'New deployment' and select 'Add-on' as the type. Note the Deployment ID, as you'll use it later.

3. Create an Add-on Manifest: The appsscript.json file, also known as the manifest file, is crucial for configuring your add-on. It defines its behavior, appearance, and integration points. You can edit this directly in the script editor under 'Project settings' > 'appsscript.json'. Key fields include:
   • timeZone
   • dependencies
   • exceptionLogging
   • runtimeVersion
   • oauthScopes (essential for permissions)
   • addOns (defines how your add-on integrates with different Workspace applications)

4. Develop Your User Interface (if applicable): For add-ons that go beyond simple menu items, you'll build out UIs using HTML Service or CardService. HTML Service allows you to create rich, web-like interfaces using standard HTML, CSS, and JavaScript. CardService is used for creating interactive cards within Google Workspace, offering a more streamlined and context-aware experience. You'll typically use functions like showSidebar(), showModalDialog(), or showCard() from your script to display these UIs.

graph TD;
    A[User opens Google Sheet] --> B{Add-on is installed};
    B -- Yes --> C[Add-on menu appears];
    C --> D[User clicks menu item];
    D --> E{Trigger function in script};
    E --> F[Display UI (Sidebar/Dialog/Card)];
    F --> G[User interacts with UI];
    G --> H[Script performs action];
    H --> I[Update Sheet/Display result];
    B -- No --> J[Prompt user to install Add-on];

5. Test Thoroughly: Before submitting for review, test your add-on extensively in a test account. Ensure all features work as expected, error messages are clear, and the user experience is smooth across different scenarios and devices. Test the installation process itself to identify any potential roadblocks.

6. Submit to the Google Workspace Marketplace:
   • Developer Console: You'll need to register as a Google Cloud developer and create a project for your add-on. Navigate to the Google Cloud Console and set up your project.
   • Publishing Process: Within the Google Cloud Console, you'll find options to create and manage your add-on listing. This involves uploading your script, providing marketing materials (description, screenshots, video), and specifying pricing if applicable.
   • Review Process: Google has a review process to ensure add-ons meet their quality, security, and policy standards. This can take some time, so be patient.

7. Ongoing Maintenance and Updates: Once published, your add-on will require ongoing maintenance. This includes addressing user feedback, fixing bugs, and updating your script to support new Google Workspace features or changes. You can deploy new versions of your add-on through the Cloud Console.

Publishing as an add-on is a rewarding way to share your creations with a wider audience and contribute to the Google Workspace ecosystem. While it involves more steps than other sharing methods, the professional integration and discoverability it offers are invaluable for impactful solutions.