How Do I Keep a Subscription Active Without Billing the Customer?

Yes, there are a couple of ways to handle this use case, depending on your needs.

Option 1: Edit the Subscription Price to $0

You can simply edit the individual customer's subscription and change the price to $0. Once this change is made, the subscription will remain active even if the customer removes their stored billing information. All future invoices for this subscription will automatically be generated with a $0 due amount and will close without requiring payment.

Option 2: Apply a 100% Off Coupon

Another way to handle this is by using a coupon. If you create a new coupon with the discount type set to 100% percentage off, you can then apply that coupon to the customer's account or subscription. This coupon will then discount all future invoices, bringing the due amount to $0. This method is a good option if you only want to temporarily stop the billings from occurring for this customer's subscription.