If you’ve installed the Shopify code snippet, you may have noticed that subscription (or recurring billing) products will show a custom product property of cf_sub_id.

It will look something like this, where X is the subscription ID corresponding to your product’s subscription settings within Cartfunnel:

cf_sub_id: X

We store the subscription ID in the Shopify cart so that this information can be forwarded to Cartfunnel’s servers later.

Cartfunnel comes with a built in code to handle this. You can tell Cartfunnel to autogenerate this code for you and install it in your Shopify theme.

To activate this functionality, go to the Shopify integration page (within Cartfunnel) and turn on the setting:

Cart updater

In certain cases, you may have to customize the code to work. If you’re not familiar with Javascript, please contact support for assistance.


To modify the code, scroll down on the same Shopify integration setting page:

Cart update code

What this piece of code does

Shopify themes generally have two styles of shopping cart: the traditional HTML cart page, and the fancier (and trickier) Ajax Drawer cart page.

If you’re using our default cart updater code, it will periodically detect the presence of cf_sub_id and update it with the correct subscription labeling.

This code can be modified to update the price as well.