ZakMcKraken

[regal yew]

Hello 👋
I'm not sure as I haven't tested this flow personally.

An alternative in this case would be using Customer Credit Balance
https://stripe.com/docs/invoicing/customer/balance#working-with-credit-balances

It applies to the next finalized invoice on to a customer

does that help @spring field ?

If I try to do that using price_data and the add_invoice_items param described on https://stripe.com/docs/billing/invoices/subscription#first-invoice-extra, it doesn't let me create a negative amount (and also, sadly, requires a product to be created ahead).
Also, How exactly are you doing this? Can you share an example?

You likely want to create a negative invoice item as shown in the example here
https://stripe.com/docs/api/invoiceitems/create

by specifying a negative amount, customer and subscription ID

[spring field]

so I'm actually trying to get away from using a credit balance because that doesn't work as it should in a tax context (aka tax gets applied to the full amount and then the credit is deducted, instead of deducting the credit and then calculating the taxes)

as I said invoice items works but I was trying to use add_invoice_items to reduce the calls

      [
        'price_data' => [
          'currency' => 'USD',
          'tax_behavior' => 'exclusive',
          'unit_amount_decimal' => -100,
        ]
      ]
    ]```

It's missing the product param but this will still return

Stripe\Exception\InvalidRequestException with message 'This value must be greater than or equal to 0 (it currently is '-0.1e3').

which doesnt make any sense since according to the documentation we should be able to use this for discounts

this feels like a bug

[rich nimbus]

You can exclude the product if you are using a Price ID but not if you are using price_data

Which we call out here: https://stripe.com/docs/api/subscriptions/create#create_subscription-add_invoice_items-price_data

[spring field]

(also maybe credit balance does work for the purpose if I use type "applied_to_invoice" I have to try that)

[rich nimbus]

That sounds like it would be closer to what you are trying to achieve

[spring field]

@rich nimbus I know, just omitted the product to show you an example

[rich nimbus]

I don't think the behavior you are seeing is a bug, just maybe not as useful as it could be

Since our docs for add_invoice_item state that, for unit_amount must be a positive integer in cents and unit_amount_decimal is the same as unit amount but accepts decimal values

[spring field]

I'll give you that

but one would expect it to behave the same as adding an invoice item

and also the fact that https://stripe.com/docs/billing/invoices/subscription#first-invoice-extra

the title is "Add an extra charge or discount on a subscription’s first invoice" but if it doesn't accept negative value, how do you add a discount?

I'm guessing you'd have to go ahead and create a product with a negative price?

[rich nimbus]

Well you don't have to create a Product record, just a Price record

[spring field]

so like a price with a non-active product beforehand

[rich nimbus]

Or you could use product_data when creating the Price to avoid a new Product record: https://stripe.com/docs/api/prices/create#create_price-product_data
Then you could provide as little as a name to indicate what the product/price is for

[spring field]

yeah that's what I meant

I was assuming product_data.active would have to be set to false so it doesn't show up in the UI

[rich nimbus]

Yes that would be a good approach

[spring field]

I think so

the reason I don't like credit balance and pending invoice items is that we could run into race conditions

aka the discount is applied to the wrong invoice

[rich nimbus]

I can understand that, since credit balances don't discriminate which invoice they are applied to

[spring field]

TY for the help, I'll try what we discussed