You can integrate Batch's snippet via Google Tag Manager by following the steps bellow:
1. Create a tag
Click on "New tag" and select "Custom HTML" as your tag configuration:
Paste your Batch snippet in the HTML textbox:
2. Define a trigger
The snippet should be triggered on all your website's pages (Select "All pages" as a firing trigger), unless there are subdomains you want to exclude, in which case you should add exceptions.
To add an exception to your tag triggers, you should create a new trigger that will be used as an exclusion trigger.
If you want to exclude all subdomains, use the following condition:
If you want to exclude a list of subdomains, use the following conditions:
Once your exclusion trigger has been created, add it to your tag's trigger settings as an exception:
That’s it, when you are all set release the new tag in staging or in production. Make sure you test your integration correctly by following the steps described here: Testing my web push integration