How to Connect Google Tag Manager API to Google Apps Script (Step-by-Step)

2025-03-28

How to Connect Google Tag Manager API to Google Apps Script (Step-by-Step)

If you’ve ever wanted to automatically pull your Google Tag Manager (GTM) container data into Google Sheets — or just run GTM API requests inside Apps Script — this guide is for you.

In this blog post, I’ll walk you through how I connected the GTM API to Google Apps Script to read container data, using nothing but code and some configuration in Google Cloud Platform.

🛠️ Why Use Apps Script for GTM?

No need for third-party tools
Easy to run and manage from Google Sheets
Perfect for automation, reporting, or building internal GTM documentation tools

✅ Step 1: Create a Google Apps Script Project

Open script.google.com
Create a new project
Name your project (e.g., “GTM API Connector”)

✅ Step 2: Link Your Project to Google Cloud

Go to Project Settings
Copy your Project Number
In the Google Cloud Console, create a new project or use an existing one
Enable the Tag Manager API v2

✅ Step 3: Set Up Your `appsscript.json` File

In Apps Script, enable the manifest file:

Go to ⚙️ Settings → Show appsscript.json

Then paste:

json

{
  "timeZone": "Europe/Zurich",
  "oauthScopes": [
    "https://www.googleapis.com/auth/script.external_request",
    "https://www.googleapis.com/auth/tagmanager.readonly"
  ]
}

This gives your script permission to connect to external APIs and read GTM containers.

✅ Step 4: Write the Script to Call GTM API

Here’s a simple function that gets your GTM containers:

javascript

function getGTMContainers() { const accessToken = ScriptApp.getOAuthToken(); const accountId = 'YOUR_GTM_ACCOUNT_ID';

const url = `https://www.googleapis.com/tagmanager/v2/accounts/${accountId}/containers`;

const response = UrlFetchApp.fetch(url, {
method: ‘get’,
headers: {
Authorization: ‘Bearer ‘ + accessToken
},
muteHttpExceptions: true
});

Logger.log(response.getContentText()); }

Make sure to replace 'YOUR_GTM_ACCOUNT_ID' with your actual GTM account ID.

✅ Step 5: Run & Authorize

Click the ▶️ Run button
Apps Script will ask for authorization
Grant access
Open View > Logs to see the API response

You should see JSON data containing your GTM containers.

🚀 What’s Next?

Now that your script is connected to GTM:

You can extend it to log tags, triggers, and variables
Or push the data into Google Sheets for documentation or audits

💬 Final Thoughts

Connecting GTM API to Apps Script opens up a ton of automation opportunities for analysts and developers. You don’t need complex frameworks or tools — just a bit of Apps Script and a GCP project.

If you’d like me to share a follow-up on how I pushed the API data into Google Sheets, let me know in the comments or reach out.

About Me

Hisham Ghanayem

Lets talk data