All packsSaaS Billing + Tax CoreSolve
stripe customer portal subscription update bypass proration
The customer portal's own defaults bypass your proration rules
If Stripe's customer portal is left free to change plans, its default proration bypasses D10/D11's carefully decided rules entirely. The pack disables it (D16).
This is one of the things SaaS Billing + Tax Core already handles. Charge per-seat subscriptions: upgrades, downgrades, failed cards, invoices and sales tax.
Is this you?
Stripe's hosted customer portal can let customers change their own plan -- convenient, except that path uses Stripe's own default proration behavior, not whatever asymmetric upgrade/downgrade rules the app carefully built (D10, D11). A customer using the portal to change plans gets billed differently than one using the app's own checkout flow, for the same action.
Why this one is easy to get wrong
Enabling subscription_update in the portal configuration looks like a feature toggle -- "let customers self-serve plan changes" -- rather than a decision that routes billing-critical logic around every proration and entitlement rule the rest of the app enforces. Nothing in the portal configuration API warns that turning this on creates a second, inconsistent path to the same outcome.
What you get instead
D16 explicitly disables subscription_update in the portal configuration, while leaving invoice_history, payment_method_update, and subscription_cancel (at period end, no mid-cycle proration) enabled. Plan and seat changes are only possible through the app's own API routes, where D10/D11's rules actually run -- the portal is scoped to what it can safely self-serve.
Source: ARCHITECTURE.md D16 — checkable in the pack you receive
How you actually use this
You don’t install a library or wire up an SDK. Your own coding agent builds the code in your project, and you keep it — no runtime dependency on us.
Step 1
Download and unzip
You get a folder: the docs that tell an agent what to build, a starting skeleton, and the test suite that decides when it's done.
Step 2
Open it in Claude Code or Cursor
Point your coding agent at the folder. Nothing to install, no account with us, no API key.
Step 3
Paste one prompt
The pack contains the exact prompt. Paste it as your first message and leave it alone — it works through the build itself, choosing a cheaper or stronger model per task.
Step 4
Run ./verify.sh
One command. It prints a pass or fail for every check. Green means the build is done — the same script we ran to produce the receipt on this page.
Typical build: about 18 minutes of your agent working, mostly unattended. Then you integrate the working module into your app the way you would any code you’d written yourself.
Why you can believe this
3 of 3 runs passedWe ran this pack from an empty folder 3 times and published exactly what happened — every check, the model, the token cost, the wall time. Not a testimonial, and not our opinion: the same verify.sh you run yourself. Read the full receipt →