Is html code of tags in Google Tag Manager visible to everyone?

Question

If I include some kind of private data like key or password in Custom HTML Code Tag in GTM will it be accessible by everyone who visit website with that container?

Answer 1

As with most tag management systems (that I know of) Google Tag Manager Code does not run on a server; instead your configured tags with all triggers and variables are packed into a javascript wrapper and injected into the html code of the currently viewed page.

As with all client-side code everything is visible - the code will be slightly obfuscated by the GTM function calls, but not so much that is no longer readable. It's not really possible to encrypt code that must be executed by the browser, else the browser would not be able to execute it.

As nyuen suggested you can even see this for yourself - enter http://www.googletagmanager.com/gtm.js?id=GTM-XXXXX into your browser (where you replace XXXXX with the id of your published container) and you can see everything you put in there, including passwords etc.