Prorate final payment when individual users cancel their $€ 9.00 paid subscriptions.

[jldec]

When users cancel a paid subscription which includes a credit allowance, like the personal paid plan, they should not be penalized for cancellations right after subscribing, or at the start of a billing period.

Effect of cancellation:

• Issue final invoice for that month.
• Usage limit drops back down to the free plan limit (500 credits).
• The charge for the $€ 9.00 flat-rate amount is pro-rated, proportional to usage or time (investigate Stripe support)

More details in discussion (internal)

[geropl]

The unused credits will remain active until the end of the billing period.

But when you cancel your subscription, your billing period ends immediately: that's why you receive an invoice. 🤔

Did we think about enabling proration in Stripe? The credit model rather well for that (because we know the exact number we want to refund).

/cc @jankeromnes bc you maybe know whether enabling proration is as easy as I hope it is.

[jankeromnes]

I would also be keen to pro-rated refund the individual base rate, instead of keeping awkwardly unattached/expiring credits around like we did before. Will look at what Stripe offers there.

[jankeromnes]

Ah, I was finally able to track down the relevant information (after getting lost in various other unrelated proration docs). Turns out it's pretty clearly indicated in the "cancel subscription" docs [1, 2]:

Should be pretty easy to add -- let's try this out.