What is sandboxed JavaScript in GTM?

Sandboxed JavaScript is a restricted subset of JavaScript used in GTM templates that removes high-risk features like direct DOM access and eval() to ensure container security and stability.

Does this skill support GTM Server-side development?

Yes, the skill includes specific implementation patterns for server-side client templates and HTTP request handling in the GTM Server-side environment.

How does it help with template permissions?

It provides guidance on configuring the 'Permissions' tab in GTM, helping you define specific allowed URLs, cookie names, and global variables to follow the principle of least privilege.

Can I use this to convert existing JavaScript snippets into GTM templates?

Absolutely. This skill specializes in identifying standard JS features that won't work in GTM and suggesting the appropriate sandboxed API alternatives like callInWindow or copyFromWindow.

GTM Custom Templates Builder

Name: GTM Custom Templates Builder
Author: henkisdabro

byhenkisdabro

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Analytics & Monitoring

Simplifies the creation of Google Tag Manager custom templates using secure sandboxed JavaScript APIs and best practices.

About

This skill empowers developers to build, debug, and test Google Tag Manager (GTM) custom templates with precision. It provides expert guidance on working within the restrictions of sandboxed JavaScript, implementing complex data manipulation, and handling secure network requests via dedicated GTM APIs. Whether you are creating custom tag templates for third-party services, developing server-side clients, or preparing templates for the Community Template Gallery, this skill ensures your code adheres to GTM’s strict security permissions and performance standards.

Key Features

Permission configuration for secure URL and cookie access
Expert sandboxed JavaScript API implementation (require, sendPixel, injectScript)
Comprehensive unit testing and mocking frameworks for template logic
8 GitHub stars
Template structure guidance for Tags, Variables, and Server-side Clients
Conversion of standard JavaScript to GTM-compliant sandboxed code

Use Cases

Developing custom tag templates for third-party marketing and analytics vendors
Migrating client-side tracking logic to GTM Server-side using custom clients
Creating complex variable templates for data layer manipulation and extraction

About

Key Features

Permission configuration for secure URL and cookie access
Expert sandboxed JavaScript API implementation (require, sendPixel, injectScript)
Comprehensive unit testing and mocking frameworks for template logic
8 GitHub stars
Template structure guidance for Tags, Variables, and Server-side Clients
Conversion of standard JavaScript to GTM-compliant sandboxed code

Use Cases

Developing custom tag templates for third-party marketing and analytics vendors
Migrating client-side tracking logic to GTM Server-side using custom clients
Creating complex variable templates for data layer manipulation and extraction