I would like to bump this thread and piggyback on @asker and @chris10’s questions to help provide resolution for the community on the mystery of the Subscription Item ID using Stripe.JS. Not to be confused with the Subscription ID, which are two different ID’s I’ve come to find out.
It appears there is no way to retrieve the Subscription Item ID via workflows, and I have not seen whether that has been confirmed by @copilot. I did email them separately and via their website customer service chat to see if I could get to the bottom of it, but I think it’s important to share here too incase something is amiss.
Here is my situation.
Upon a user signing up I created a workflow where a metered subscription is created for my user via Stripe.JS. This works well and good.
The problem is when I come to the point where I finally have to add usage units to the metered plan, the Stripe.JS workflow action to add those units requires a “Subscription Item ID”… But no where could I find how to successfully retrieve that information.
Typically the plugin is good about being able to refer to a previous results actions to obtain a bit of information, like when creating a new stripe customer, then being able to ask the plugin to retrieve results of previous step’s Stripe Customer ID, to say, to save in your bubble DB. However, that doesn’t appear to exist for the Subscription Item ID.
This is problematic for me because as you can see in the screenshot below to add usage to a plan requires the Subscription Item ID, which I errantly put the Subscription ID in before. I have no idea what I may be doing wrong, or if something was missed by the @copilot team.

What confuses me is that when a new subscriber is to added to Stripe via the sign up workflow, a Subscription Item ID (top line, prefix “si_”) is generated as evidence in the code in Stripe’s dashboard (screenshot below). However, that information does not appear able to be called upon to be retrieved into workflow actions.

When I manually take the Subscription Item ID from the Stripe dashboard code, and enter it into the (path) Subscription Item ID field in the “Stripe.JS Add Usage to a Metered Plan” workflow, it actually does work. But problem is how do we pull that data via workflows?
@copilot, can you please confirm whether we are not retrieving things properly, or if this aspect was missed in the plugin?